Vulnerability-Lookup

GHSA-W878-PJ84-3J5V

Vulnerability from github – Published: 2026-09-02 23:42 – Updated: 2026-09-02 23:42

Summary

Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection

Details

Summary

Mailpit's SMTP server reads each command line with an unbounded bufio.Reader.ReadString('\n') before parsing the command or enforcing any protocol length limit. A remote SMTP client can send an oversized single command line and force Mailpit to allocate attacker-controlled memory before the server returns a syntax error or times out, even though RFC 5321 limits SMTP command lines to 512 octets including CRLF.

Technical Details

Mailpit enables SMTP by default. config/config.go sets SMTPListen = "[::]:1025", and cmd/root.go calls smtpd.Listen() during normal startup. The SMTP server configures recipient and message DATA size limits in internal/smtpd/main.go, including the default 50 MiB MaxMessageSize, but those limits do not apply to command lines.

The vulnerable path is in the SMTP command loop. internal/smtpd/smtpd.go calls s.readLine() for every command before parsing the verb or arguments:

line, err := s.readLine()
if err != nil {
    if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
        s.writef("421 4.4.2 %s %s ESMTP Service closing transmission channel after timeout exceeded", s.srv.Hostname, s.srv.AppName)
    }
    break
}

verb, args := s.parseLine(line)

readLine() then buffers until newline without a maximum length:

func (s *session) readLine() (string, error) {
    if s.srv.Timeout > 0 {
        _ = s.conn.SetReadDeadline(time.Now().Add(s.srv.Timeout))
    }

    line, err := s.br.ReadString('\n')
    if err != nil {
        return "", err
    }
    line = strings.TrimSpace(line)
    return line, err
}

This violates the SMTP command-line invariant before later validation can help. Address length validation in extractAndValidateAddress() runs only after the entire command line has already been buffered and parsed. The DATA reader has a separate srv.MaxSize check, but the issue is pre-DATA command input.

PoV

The following bounded test exercises the same command reader with a normal NOOP control and an 8 MiB oversized command line:

package smtpd

import (
    "bufio"
    "bytes"
    "strings"
    "testing"
)

func TestUnboundedSMTPCommandLinePoV(t *testing.T) {
    short := "NOOP\r\n"
    shortSession := session{srv: &Server{}, br: bufio.NewReader(strings.NewReader(short))}
    shortLine, err := shortSession.readLine()
    if err != nil {
        t.Fatalf("short control readLine failed: %v", err)
    }
    t.Logf("short control: accepted len=%d command=%q", len(shortLine), shortLine)

    oversizedLen := 8 * 1024 * 1024
    oversized := strings.Repeat("X", oversizedLen) + "\r\n"
    oversizedSession := session{srv: &Server{}, br: bufio.NewReader(bytes.NewBufferString(oversized))}
    oversizedLine, err := oversizedSession.readLine()
    if err != nil {
        t.Fatalf("oversized readLine failed: %v", err)
    }
    t.Logf("oversized command: accepted len=%d; RFC 5321 command-line limit is 512 octets including CRLF", len(oversizedLine))

    if len(oversizedLine) != oversizedLen {
        t.Fatalf("readLine length = %d, want %d", len(oversizedLine), oversizedLen)
    }
    if len(oversizedLine) <= 512 {
        t.Fatalf("oversized command did not exceed SMTP command-line limit")
    }
}

PoC

From a Mailpit checkout, save the PoV above as internal/smtpd/smtp_command_line_pov_test.go and run:

docker run --rm -v "$PWD:/src" -w /src golang:1.25 go test ./internal/smtpd -run TestUnboundedSMTPCommandLinePoV -v

On current develop commit cd7661fd5b23cce1e218b583b21e157cfa612051, the test prints:

=== RUN   TestUnboundedSMTPCommandLinePoV
    smtp_command_line_pov_test.go:17: short control: accepted len=4 command="NOOP"
    smtp_command_line_pov_test.go:26: oversized command: accepted len=8388608; RFC 5321 command-line limit is 512 octets including CRLF
--- PASS: TestUnboundedSMTPCommandLinePoV (0.01s)
PASS
ok      github.com/axllent/mailpit/internal/smtpd   0.017s

The same test against release v1.30.3 commit 6acf5b8f942ab0e007b1227d31dfb3c3303e8d13 prints:

=== RUN   TestUnboundedSMTPCommandLinePoV
    smtp_command_line_pov_test.go:17: short control: accepted len=4 command="NOOP"
    smtp_command_line_pov_test.go:26: oversized command: accepted len=8388608; RFC 5321 command-line limit is 512 octets including CRLF
--- PASS: TestUnboundedSMTPCommandLinePoV (0.02s)
PASS
ok      github.com/axllent/mailpit/internal/smtpd   0.020s

The NOOP control shows the normal reader path. The oversized case shows the parser accepting an 8 MiB command line into memory instead of rejecting at the SMTP command-line limit.

Impact

An unauthenticated remote client that can reach Mailpit's SMTP listener can force heap allocation proportional to a single command line before any SMTP command is parsed. Repeating the input across concurrent connections can consume process memory and degrade or deny Mailpit service availability. This is distinct from message DATA size handling: the default MaxMessageSize cap is enforced after DATA, while the command-line reader is reached before DATA and before MAIL FROM SIZE= handling.

Suggested advisory metadata: CWE-400 (Uncontrolled Resource Consumption). Conservative CVSS 3.1 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, base score 7.5 (High). If a deployment explicitly binds SMTP to trusted loopback-only clients, environmental severity may be lower; the project default is a network SMTP listener on [::]:1025.

Suggested Fix

Bound SMTP command-line reads before buffering the full line. For ordinary SMTP commands, reject input exceeding RFC 5321's 512-octet command-line limit including CRLF, returning a 500 5.5.2-style command-line-too-long response before allocating the entire attacker-controlled line. Apply the same pre-parse bound to AUTH continuation lines because handleAuthLogin(), handleAuthPlain(), and handleAuthCramMD5() also call readLine(). Consider adding a similar POP3 command-line cap in internal/pop3/server.go, where the optional POP3 server also uses ReadString('\n') for commands.

Regression tests should cover a normal short command, an over-limit command line, and over-limit AUTH continuation input. They should assert that the over-limit cases fail without returning the oversized string to command parsing.

Affected Package/Versions

Confirmed affected:

Current develop: cd7661fd5b23cce1e218b583b21e157cfa612051
Latest release: v1.30.3, tag commit 6acf5b8f942ab0e007b1227d31dfb3c3303e8d13, published 2026-06-27

No fixed version was identified during this review.

Advisory History

The closest published Mailpit advisory is GHSA-fpxj-m5q8-fphw, which covers unauthenticated memory exhaustion through unlimited SMTP DATA and /api/v1/send body sizes. This report is different: it targets the pre-DATA SMTP command-line reader before srv.MaxSize, MAIL FROM SIZE=, or DATA handling applies.

Other published Mailpit advisories checked were GHSA-28pq-6qxg-wg5r for HTTP JSON body limits, GHSA-54wq-72mp-cq7c for SMTP header injection, GHSA-w4vj-r5pg-3722 for proxy CSS map concurrency, GHSA-qx5x-85p8-vg4j for dump path traversal, the SSRF/link-check/proxy advisories GHSA-8v65-47jx-7mfr, GHSA-mpf7-p9x7-96r3, GHSA-6jxm-fv7w-rw5j, GHSA-j3fj-qppj-fmmc, GHSA-w4mc-hhc6-xp28, and GHSA-524m-q5m7-79mm for CSWSH. None of these describe unbounded SMTP command-line buffering.

Public Mailpit issue searches for SMTP command line too long ReadString, SMTP 512 octets command line, SMTP memory DoS command line, and ReadString smtpd found no matching issue. Public commit searches for ReadString smtpd, command line too long, and MaxMessageSize smtp found no matching fix. No prior submitted, ready-for-review, or completed-but-unsubmitted Mailpit report available in the review materials matched this root cause.

References

RFC 5321 section 4.5.3.1.4, command-line length limit: https://www.rfc-editor.org/rfc/rfc5321#section-4.5.3.1.4
Mailpit security policy: https://github.com/axllent/mailpit/security/policy
GHSA-fpxj-m5q8-fphw: https://github.com/axllent/mailpit/security/advisories/GHSA-fpxj-m5q8-fphw
GHSA-28pq-6qxg-wg5r: https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r
GHSA-54wq-72mp-cq7c: https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.30.3"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/axllent/mailpit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.30.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-67445"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-02T23:42:25Z",
    "nvd_published_at": "2026-08-20T21:17:07Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nMailpit\u0027s SMTP server reads each command line with an unbounded `bufio.Reader.ReadString(\u0027\\n\u0027)` before parsing the command or enforcing any protocol length limit. A remote SMTP client can send an oversized single command line and force Mailpit to allocate attacker-controlled memory before the server returns a syntax error or times out, even though RFC 5321 limits SMTP command lines to 512 octets including CRLF.\n\n## Technical Details\n\nMailpit enables SMTP by default. `config/config.go` sets `SMTPListen = \"[::]:1025\"`, and `cmd/root.go` calls `smtpd.Listen()` during normal startup. The SMTP server configures recipient and message DATA size limits in `internal/smtpd/main.go`, including the default 50 MiB `MaxMessageSize`, but those limits do not apply to command lines.\n\nThe vulnerable path is in the SMTP command loop. `internal/smtpd/smtpd.go` calls `s.readLine()` for every command before parsing the verb or arguments:\n\n```go\nline, err := s.readLine()\nif err != nil {\n    if netErr, ok := err.(net.Error); ok \u0026\u0026 netErr.Timeout() {\n        s.writef(\"421 4.4.2 %s %s ESMTP Service closing transmission channel after timeout exceeded\", s.srv.Hostname, s.srv.AppName)\n    }\n    break\n}\n\nverb, args := s.parseLine(line)\n```\n\n`readLine()` then buffers until newline without a maximum length:\n\n```go\nfunc (s *session) readLine() (string, error) {\n    if s.srv.Timeout \u003e 0 {\n        _ = s.conn.SetReadDeadline(time.Now().Add(s.srv.Timeout))\n    }\n\n    line, err := s.br.ReadString(\u0027\\n\u0027)\n    if err != nil {\n        return \"\", err\n    }\n    line = strings.TrimSpace(line)\n    return line, err\n}\n```\n\nThis violates the SMTP command-line invariant before later validation can help. Address length validation in `extractAndValidateAddress()` runs only after the entire command line has already been buffered and parsed. The DATA reader has a separate `srv.MaxSize` check, but the issue is pre-DATA command input.\n\n## PoV\n\nThe following bounded test exercises the same command reader with a normal `NOOP` control and an 8 MiB oversized command line:\n\n```go\npackage smtpd\n\nimport (\n    \"bufio\"\n    \"bytes\"\n    \"strings\"\n    \"testing\"\n)\n\nfunc TestUnboundedSMTPCommandLinePoV(t *testing.T) {\n    short := \"NOOP\\r\\n\"\n    shortSession := session{srv: \u0026Server{}, br: bufio.NewReader(strings.NewReader(short))}\n    shortLine, err := shortSession.readLine()\n    if err != nil {\n        t.Fatalf(\"short control readLine failed: %v\", err)\n    }\n    t.Logf(\"short control: accepted len=%d command=%q\", len(shortLine), shortLine)\n\n    oversizedLen := 8 * 1024 * 1024\n    oversized := strings.Repeat(\"X\", oversizedLen) + \"\\r\\n\"\n    oversizedSession := session{srv: \u0026Server{}, br: bufio.NewReader(bytes.NewBufferString(oversized))}\n    oversizedLine, err := oversizedSession.readLine()\n    if err != nil {\n        t.Fatalf(\"oversized readLine failed: %v\", err)\n    }\n    t.Logf(\"oversized command: accepted len=%d; RFC 5321 command-line limit is 512 octets including CRLF\", len(oversizedLine))\n\n    if len(oversizedLine) != oversizedLen {\n        t.Fatalf(\"readLine length = %d, want %d\", len(oversizedLine), oversizedLen)\n    }\n    if len(oversizedLine) \u003c= 512 {\n        t.Fatalf(\"oversized command did not exceed SMTP command-line limit\")\n    }\n}\n```\n\n## PoC\n\nFrom a Mailpit checkout, save the PoV above as `internal/smtpd/smtp_command_line_pov_test.go` and run:\n\n```fish\ndocker run --rm -v \"$PWD:/src\" -w /src golang:1.25 go test ./internal/smtpd -run TestUnboundedSMTPCommandLinePoV -v\n```\n\nOn current `develop` commit `cd7661fd5b23cce1e218b583b21e157cfa612051`, the test prints:\n\n```text\n=== RUN   TestUnboundedSMTPCommandLinePoV\n    smtp_command_line_pov_test.go:17: short control: accepted len=4 command=\"NOOP\"\n    smtp_command_line_pov_test.go:26: oversized command: accepted len=8388608; RFC 5321 command-line limit is 512 octets including CRLF\n--- PASS: TestUnboundedSMTPCommandLinePoV (0.01s)\nPASS\nok  \tgithub.com/axllent/mailpit/internal/smtpd\t0.017s\n```\n\nThe same test against release `v1.30.3` commit `6acf5b8f942ab0e007b1227d31dfb3c3303e8d13` prints:\n\n```text\n=== RUN   TestUnboundedSMTPCommandLinePoV\n    smtp_command_line_pov_test.go:17: short control: accepted len=4 command=\"NOOP\"\n    smtp_command_line_pov_test.go:26: oversized command: accepted len=8388608; RFC 5321 command-line limit is 512 octets including CRLF\n--- PASS: TestUnboundedSMTPCommandLinePoV (0.02s)\nPASS\nok  \tgithub.com/axllent/mailpit/internal/smtpd\t0.020s\n```\n\nThe `NOOP` control shows the normal reader path. The oversized case shows the parser accepting an 8 MiB command line into memory instead of rejecting at the SMTP command-line limit.\n\n## Impact\n\nAn unauthenticated remote client that can reach Mailpit\u0027s SMTP listener can force heap allocation proportional to a single command line before any SMTP command is parsed. Repeating the input across concurrent connections can consume process memory and degrade or deny Mailpit service availability. This is distinct from message DATA size handling: the default `MaxMessageSize` cap is enforced after `DATA`, while the command-line reader is reached before DATA and before `MAIL FROM SIZE=` handling.\n\nSuggested advisory metadata: CWE-400 (Uncontrolled Resource Consumption). Conservative CVSS 3.1 vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, base score 7.5 (High). If a deployment explicitly binds SMTP to trusted loopback-only clients, environmental severity may be lower; the project default is a network SMTP listener on `[::]:1025`.\n\n## Suggested Fix\n\nBound SMTP command-line reads before buffering the full line. For ordinary SMTP commands, reject input exceeding RFC 5321\u0027s 512-octet command-line limit including CRLF, returning a `500 5.5.2`-style command-line-too-long response before allocating the entire attacker-controlled line. Apply the same pre-parse bound to AUTH continuation lines because `handleAuthLogin()`, `handleAuthPlain()`, and `handleAuthCramMD5()` also call `readLine()`. Consider adding a similar POP3 command-line cap in `internal/pop3/server.go`, where the optional POP3 server also uses `ReadString(\u0027\\n\u0027)` for commands.\n\nRegression tests should cover a normal short command, an over-limit command line, and over-limit AUTH continuation input. They should assert that the over-limit cases fail without returning the oversized string to command parsing.\n\n## Affected Package/Versions\n\nConfirmed affected:\n\n- Current `develop`: `cd7661fd5b23cce1e218b583b21e157cfa612051`\n- Latest release: `v1.30.3`, tag commit `6acf5b8f942ab0e007b1227d31dfb3c3303e8d13`, published 2026-06-27\n\nNo fixed version was identified during this review.\n\n## Advisory History\n\nThe closest published Mailpit advisory is `GHSA-fpxj-m5q8-fphw`, which covers unauthenticated memory exhaustion through unlimited SMTP DATA and `/api/v1/send` body sizes. This report is different: it targets the pre-DATA SMTP command-line reader before `srv.MaxSize`, `MAIL FROM SIZE=`, or DATA handling applies.\n\nOther published Mailpit advisories checked were `GHSA-28pq-6qxg-wg5r` for HTTP JSON body limits, `GHSA-54wq-72mp-cq7c` for SMTP header injection, `GHSA-w4vj-r5pg-3722` for proxy CSS map concurrency, `GHSA-qx5x-85p8-vg4j` for dump path traversal, the SSRF/link-check/proxy advisories `GHSA-8v65-47jx-7mfr`, `GHSA-mpf7-p9x7-96r3`, `GHSA-6jxm-fv7w-rw5j`, `GHSA-j3fj-qppj-fmmc`, `GHSA-w4mc-hhc6-xp28`, and `GHSA-524m-q5m7-79mm` for CSWSH. None of these describe unbounded SMTP command-line buffering.\n\nPublic Mailpit issue searches for `SMTP command line too long ReadString`, `SMTP 512 octets command line`, `SMTP memory DoS command line`, and `ReadString smtpd` found no matching issue. Public commit searches for `ReadString smtpd`, `command line too long`, and `MaxMessageSize smtp` found no matching fix. No prior submitted, ready-for-review, or completed-but-unsubmitted Mailpit report available in the review materials matched this root cause.\n\n## References\n\n- RFC 5321 section 4.5.3.1.4, command-line length limit: https://www.rfc-editor.org/rfc/rfc5321#section-4.5.3.1.4\n- Mailpit security policy: https://github.com/axllent/mailpit/security/policy\n- `GHSA-fpxj-m5q8-fphw`: https://github.com/axllent/mailpit/security/advisories/GHSA-fpxj-m5q8-fphw\n- `GHSA-28pq-6qxg-wg5r`: https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r\n- `GHSA-54wq-72mp-cq7c`: https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c",
  "id": "GHSA-w878-pj84-3j5v",
  "modified": "2026-09-02T23:42:25Z",
  "published": "2026-09-02T23:42:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-w878-pj84-3j5v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67445"
    },
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/commit/993bed95b3c74d95231af93bd0e0d4c3d5b4db4d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/axllent/mailpit"
    },
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/releases/tag/v1.30.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection"
}

CVE-2026-67445 (GCVE-0-2026-67445)

Vulnerability from cvelistv5 – Published: 2026-08-20 21:13 – Updated: 2026-08-21 21:45

Title

Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection

Summary

Mailpit is an email testing tool and API for developers. Prior to 1.30.4, Mailpit reads SMTP commands through internal/smtpd/smtpd.go session.readLine() using bufio.Reader.ReadString before session.parseLine() parses the verb or the RFC 5321 512-octet command-line limit is enforced. An unauthenticated remote SMTP client can send an oversized single command line that is fully allocated before syntax rejection or timeout, and the normal MaxMessageSize and DATA limits do not apply to this pre-DATA path. The same command reader is used by handleAuthLogin(), handleAuthPlain(), and handleAuthCramMD5() continuation lines, so concurrent oversized inputs can create memory pressure and reduce service availability. This issue is fixed in version 1.30.4.

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 21:09 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/axllent/mailpit/security/advis…	x_refsource_CONFIRM
https://github.com/axllent/mailpit/commit/993bed9…	x_refsource_MISC
https://github.com/axllent/mailpit/releases/tag/v1.30.4	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
axllent	mailpit	Affected: < 1.30.4

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-67445",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-21T21:09:33.233187Z",
                "version": "2.0.3"
              },
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            }
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        "providerMetadata": {
          "dateUpdated": "2026-08-21T21:45:36.467Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "product": "mailpit",
          "vendor": "axllent",
          "versions": [
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              "status": "affected",
              "version": "\u003c 1.30.4"
            }
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      "descriptions": [
        {
          "lang": "en",
          "value": "Mailpit is an email testing tool and API for developers. Prior to 1.30.4, Mailpit reads SMTP commands through internal/smtpd/smtpd.go session.readLine() using bufio.Reader.ReadString before session.parseLine() parses the verb or the RFC 5321 512-octet command-line limit is enforced. An unauthenticated remote SMTP client can send an oversized single command line that is fully allocated before syntax rejection or timeout, and the normal MaxMessageSize and DATA limits do not apply to this pre-DATA path. The same command reader is used by handleAuthLogin(), handleAuthPlain(), and handleAuthCramMD5() continuation lines, so concurrent oversized inputs can create memory pressure and reduce service availability. This issue is fixed in version 1.30.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
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      "problemTypes": [
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      "providerMetadata": {
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      "references": [
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          "name": "https://github.com/axllent/mailpit/security/advisories/GHSA-w878-pj84-3j5v",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-w878-pj84-3j5v"
        },
        {
          "name": "https://github.com/axllent/mailpit/commit/993bed95b3c74d95231af93bd0e0d4c3d5b4db4d",
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          "url": "https://github.com/axllent/mailpit/commit/993bed95b3c74d95231af93bd0e0d4c3d5b4db4d"
        },
        {
          "name": "https://github.com/axllent/mailpit/releases/tag/v1.30.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/axllent/mailpit/releases/tag/v1.30.4"
        }
      ],
      "source": {
        "advisory": "GHSA-w878-pj84-3j5v",
        "discovery": "UNKNOWN"
      },
      "title": "Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-67445",
    "datePublished": "2026-08-20T21:13:27.481Z",
    "dateReserved": "2026-07-29T15:07:24.992Z",
    "dateUpdated": "2026-08-21T21:45:36.467Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-W878-PJ84-3J5V

Summary

Technical Details

PoV

PoC

Impact

Suggested Fix

Affected Package/Versions

Advisory History

References

CVE-2026-67445 (GCVE-0-2026-67445)

Tags

Sightings

Nomenclature