Vulnerability-Lookup

GHSA-2P26-P43X-FHP8

Vulnerability from github – Published: 2026-07-09 23:19 – Updated: 2026-07-09 23:19

Summary

mint: Unbounded CONTINUATION/HEADERS frame accumulation (CONTINUATION flood)

Details

Summary

Mint's HTTP/2 client accumulates CONTINUATION header-block fragments into a per-connection buffer with no cap on size or frame count. A malicious or compromised HTTP/2 server can drive the client's memory to arbitrary size by streaming an endless chain of CONTINUATION frames after a HEADERS frame that omits END_HEADERS, causing memory exhaustion and BEAM process death. A single connection to an attacker-controlled HTTP/2 endpoint is sufficient.

Details

When Mint's HTTP/2 receive path observes a HEADERS frame without the END_HEADERS flag, 'Elixir.Mint.HTTP2':handle_headers/3 parks the unparsed header-block fragment in conn.headers_being_processed. Every subsequent CONTINUATION frame on that stream is then appended to the accumulator by 'Elixir.Mint.HTTP2':handle_continuation/3.

Nothing in the receive path bounds this accumulator: there is no per-stream size cap, no CONTINUATION frame-count cap, and max_header_list_size is only enforced on outgoing requests (its default is :infinity, and the only enforcement helper inspects server_settings for request encoding, never inbound header blocks). Each CONTINUATION payload can be up to the peer-advertised SETTINGS_MAX_FRAME_SIZE, so the attacker can grow headers_being_processed to arbitrary size at line rate.

PoC

Stand up a raw TCP server that speaks the HTTP/2 handshake.
After the client's request HEADERS arrives, respond with a HEADERS frame on stream 1 with flags = 0 (no END_HEADERS, no END_STREAM) and an empty header-block fragment.
Stream CONTINUATION frames on stream 1, each with flags = 0 and a payload up to SETTINGS_MAX_FRAME_SIZE. Never set END_HEADERS.
The client's process memory grows linearly with the flood and the BEAM process eventually crashes with OOM.

Impact

Remote, unauthenticated denial-of-service against any process using Mint as an HTTP/2 client against an untrusted or attacker-influenced server. A single connection is sufficient to drive memory to arbitrary size and crash the BEAM process. The default Mint configuration is vulnerable; no client-side opt-in is required. Scored CVSS v4.0 8.2 (HIGH).

Workarounds

Restrict Mint to HTTP/1 on connections to untrusted servers by passing protocols: [:http1] to 'Elixir.Mint.HTTP':connect/4. This avoids the vulnerable HTTP/2 receive path entirely, at the cost of losing HTTP/2 for those connections.

Resources

Introduction commit: https://github.com/elixir-mint/mint/commit/596ca4304504be68939c4929e0831557097962b8
Patch commit: https://github.com/elixir-mint/mint/commit/b662d127d3028b5426c88d4c9cc7fe430491a10b

Severity

8.2 (High)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "mint"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49754"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-09T23:19:23Z",
    "nvd_published_at": "2026-06-02T16:16:44Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nMint\u0027s HTTP/2 client accumulates `CONTINUATION` header-block fragments into a per-connection buffer with no cap on size or frame count. A malicious or compromised HTTP/2 server can drive the client\u0027s memory to arbitrary size by streaming an endless chain of `CONTINUATION` frames after a `HEADERS` frame that omits `END_HEADERS`, causing memory exhaustion and BEAM process death. A single connection to an attacker-controlled HTTP/2 endpoint is sufficient.\n\n### Details\n\nWhen Mint\u0027s HTTP/2 receive path observes a `HEADERS` frame without the `END_HEADERS` flag, `\u0027Elixir.Mint.HTTP2\u0027:handle_headers/3` parks the unparsed header-block fragment in `conn.headers_being_processed`. Every subsequent `CONTINUATION` frame on that stream is then appended to the accumulator by `\u0027Elixir.Mint.HTTP2\u0027:handle_continuation/3`.\n\nNothing in the receive path bounds this accumulator: there is no per-stream size cap, no `CONTINUATION` frame-count cap, and `max_header_list_size` is only enforced on outgoing requests (its default is `:infinity`, and the only enforcement helper inspects `server_settings` for request encoding, never inbound header blocks). Each `CONTINUATION` payload can be up to the peer-advertised `SETTINGS_MAX_FRAME_SIZE`, so the attacker can grow `headers_being_processed` to arbitrary size at line rate.\n\n### PoC\n\n1. Stand up a raw TCP server that speaks the HTTP/2 handshake.\n2. After the client\u0027s request `HEADERS` arrives, respond with a `HEADERS` frame on stream 1 with `flags = 0` (no `END_HEADERS`, no `END_STREAM`) and an empty header-block fragment.\n3. Stream `CONTINUATION` frames on stream 1, each with `flags = 0` and a payload up to `SETTINGS_MAX_FRAME_SIZE`. Never set `END_HEADERS`.\n4. The client\u0027s process memory grows linearly with the flood and the BEAM process eventually crashes with OOM.\n\n### Impact\n\nRemote, unauthenticated denial-of-service against any process using Mint as an HTTP/2 client against an untrusted or attacker-influenced server. A single connection is sufficient to drive memory to arbitrary size and crash the BEAM process. The default Mint configuration is vulnerable; no client-side opt-in is required. Scored CVSS v4.0 8.2 (HIGH).\n\n## Workarounds\n\nRestrict Mint to HTTP/1 on connections to untrusted servers by passing `protocols: [:http1]` to `\u0027Elixir.Mint.HTTP\u0027:connect/4`. This avoids the vulnerable HTTP/2 receive path entirely, at the cost of losing HTTP/2 for those connections.\n\n## Resources\n\n* Introduction commit: https://github.com/elixir-mint/mint/commit/596ca4304504be68939c4929e0831557097962b8\n* Patch commit: https://github.com/elixir-mint/mint/commit/b662d127d3028b5426c88d4c9cc7fe430491a10b",
  "id": "GHSA-2p26-p43x-fhp8",
  "modified": "2026-07-09T23:19:23Z",
  "published": "2026-07-09T23:19:23Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elixir-mint/mint/security/advisories/GHSA-2p26-p43x-fhp8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49754"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elixir-mint/mint/commit/b662d127d3028b5426c88d4c9cc7fe430491a10b"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-49754.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elixir-mint/mint"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-49754"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "mint: Unbounded CONTINUATION/HEADERS frame accumulation (CONTINUATION flood)"
}

CVE-2026-49754 (GCVE-0-2026-49754)

Vulnerability from cvelistv5 – Published: 2026-06-02 14:15 – Updated: 2026-06-02 19:14

Title

HTTP/2 CONTINUATION flood in Mint client via unbounded header-block accumulation

Summary

Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint Mint allows attacker-controlled HTTP/2 servers to exhaust memory in a Mint client (HTTP/2 CONTINUATION flood). When Mint's HTTP/2 receive path observes a HEADERS frame without the END_HEADERS flag, the unparsed header-block fragment is parked in conn.headers_being_processed, and every subsequent CONTINUATION frame on that stream is appended to the accumulator. Nothing in the receive path caps the accumulator: there is no per-stream size limit, no CONTINUATION frame-count limit, and max_header_list_size is only enforced on outgoing requests, never on inbound header blocks (its default is :infinity). A malicious or compromised HTTP/2 server can stream an endless sequence of CONTINUATION frames (each up to the peer-advertised SETTINGS_MAX_FRAME_SIZE) and drive the client's iolist to arbitrary size, causing memory exhaustion and BEAM process death. A single connection to an attacker-controlled HTTP/2 endpoint is sufficient. This issue affects mint: from 0.1.0 before 1.9.0.

Severity

8.2 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

EEF

References

4 references

URL	Tags
https://github.com/elixir-mint/mint/security/advi…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-49754.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-49754	related
https://github.com/elixir-mint/mint/commit/b662d1…	patch

Impacted products

2 products

Vendor	Product	Version
elixir-mint	mint	Affected: 0.1.0 , < 1.9.0 (semver) cpe:2.3:a:elixir-mint:mint::::::::
elixir-mint	mint	Affected: 596ca4304504be68939c4929e0831557097962b8 , < b662d127d3028b5426c88d4c9cc7fe430491a10b (git) cpe:2.3:a:elixir-mint:mint::::::::

Credits

Peter Ullrich Eric Meadows-Jönsson Jonatan Männchen / EEF

Show details on NVD website

JSON

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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.

Action not permitted

GHSA-2P26-P43X-FHP8

Summary

Details

PoC

Impact

Workarounds

Resources

CVE-2026-49754 (GCVE-0-2026-49754)

Tags

Sightings

Nomenclature