RUSTSEC-2026-0348 (GHSA-H2V8-394M-P7VV)

Vulnerability from osv_rustsec – Published: 2026-10-14 12:00 – Updated: 2026-10-14 13:17 – Source website
VLAI
Summary
Brotli certificate decompression can allocate up to 1 GiB before authentication
Details

The built-in Brotli certificate decompressor (enabled by the non-default brotli crate feature) bounded the size of the decompressed output, but accepted a peer-selected history window. Brotli's large-window extension was enabled, so a five-byte header could cause an allocation of 1 GiB. A peer can abort a process whose allocator cannot satisfy that request.

No trusted certificate is required by the attacker. Affected configurations are:

  • clients that enable the brotli feature and connect to a malicious server, and
  • servers that enable the brotli feature and request client certificates.

Applications that do not enable the brotli feature are not affected.

Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "denial-of-service"
        ],
        "cvss": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "rustls",
        "purl": "pkg:cargo/rustls"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.23.9"
            },
            {
              "fixed": "0.23.46"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "GHSA-h2v8-394m-p7vv"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "The built-in Brotli certificate decompressor (enabled by the non-default\n`brotli` crate feature) bounded the size of the decompressed output, but\naccepted a peer-selected history window. Brotli\u0027s large-window extension was\nenabled, so a five-byte header could cause an allocation of 1 GiB. A peer can\nabort a process whose allocator cannot satisfy that request.\n\nNo trusted certificate is required by the attacker. Affected configurations are:\n\n- clients that enable the `brotli` feature and connect to a malicious server, and\n- servers that enable the `brotli` feature and request client certificates.\n\nApplications that do not enable the `brotli` feature are not affected.",
  "id": "RUSTSEC-2026-0348",
  "modified": "2026-10-14T13:17:45Z",
  "published": "2026-10-14T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/rustls"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0348.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rustls/rustls/pull/3297"
    }
  ],
  "related": [],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Brotli certificate decompression can allocate up to 1 GiB before authentication"
}



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