Vulnerability-Lookup

CVE-2026-90467 (GCVE-0-2026-90467)

Vulnerability from cvelistv5 – Published: 2026-09-12 01:50 – Updated: 2026-09-12 01:50

Title

aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addresses

Summary

aiosmtplib before 5.1.3 fails to properly validate email addresses supplied by callers, allowing attackers to inject ESMTP parameters into MAIL FROM and RCPT TO command lines. Attackers can craft malicious addresses containing spaces and angle brackets to append parameters like AUTH, NOTIFY, or ORCPT to envelope commands, forging authenticated identities or forcing delivery notifications to third parties.

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

4 (Medium)


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

CWE

CWE-88 - Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

Assigner

VulnCheck mitre root

References

5 references

URL	Tags
https://github.com/cole/aiosmtplib/commit/2e1b210…	patch
https://github.com/cole/aiosmtplib/releases/tag/v5.1.3	release-notes
https://github.com/cole/aiosmtplib/blob/v5.1.2/sr…	technical-description
https://github.com/cole/aiosmtplib	product
https://www.vulncheck.com/advisories/aiosmtplib-b…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
cole	aiosmtplib	Affected: 0 , < 5.1.3 (semver) Unaffected: 5.1.3 (semver)	guessed

Date Public

2026-09-07 00:00

Credits

Alfie Goh Li Heng

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:pypi/aiosmtplib",
          "product": "aiosmtplib",
          "vendor": "cole",
          "versions": [
            {
              "lessThan": "5.1.3",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.1.3",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Alfie Goh Li Heng"
        }
      ],
      "datePublic": "2026-09-07T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "aiosmtplib before 5.1.3 fails to properly validate email addresses supplied by callers, allowing attackers to inject ESMTP parameters into MAIL FROM and RCPT TO command lines. Attackers can craft malicious addresses containing spaces and angle brackets to append parameters like AUTH, NOTIFY, or ORCPT to envelope commands, forging authenticated identities or forcing delivery notifications to third parties."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-88",
              "description": "Improper Neutralization of Argument Delimiters in a Command (\u0027Argument Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-12T01:50:34.534Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Patch Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/cole/aiosmtplib/commit/2e1b210714974ccc9efd0d09a8f846cb9aeaaec2"
        },
        {
          "name": "aiosmtplib v5.1.3 Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/cole/aiosmtplib/releases/tag/v5.1.3"
        },
        {
          "name": "Unvalidated quote_address() in v5.1.2",
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/cole/aiosmtplib/blob/v5.1.2/src/aiosmtplib/email.py"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/cole/aiosmtplib"
        },
        {
          "name": "VulnCheck Advisory: aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addresses",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/aiosmtplib-before-5.1.3-esmtp-parameter-injection-via-unvalidated-addresses"
        }
      ],
      "title": "aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addresses",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-90467",
    "datePublished": "2026-09-12T01:50:34.534Z",
    "dateReserved": "2026-09-11T23:36:20.310Z",
    "dateUpdated": "2026-09-12T01:50:34.534Z",
    "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

CVE-2026-90467 (GCVE-0-2026-90467)

Tags

Sightings

Nomenclature