RUSTSEC-2026-0429 (CVE-2026-115909)

Vulnerability from osv_rustsec – Published: 2026-10-22 12:00 – Updated: 2026-11-02 09:50 – Source website
VLAI
Summary
zip: `ZipArchive::extract` aborts the process on a symlink entry with a large declared size
Details

ZipArchive::extract() sizes the symlink-target buffer from the uncompressed size declared in the central directory record, before reading a single byte of entry data:

let mut target = Vec::with_capacity(file.size() as usize);

Both inputs are attacker-controlled. ZipFile::size() returns uncompressed_size verbatim from the central directory, widened to a full u64 by a ZIP64 extended-information extra field, and is never cross-checked against the compressed size, the remaining archive length, or any platform-appropriate bound for a symlink target. ZipFile::is_symlink() is decided entirely by the S_IFLNK bit of the external-attributes field.

Vec::with_capacity() is infallible: when the reservation is refused it calls handle_alloc_error() and aborts the process. This is not a Rust panic. It is not caught by catch_unwind(), is unaffected by panic = "unwind", and is not contained by running the call on a worker thread.

A 112-byte archive is sufficient. One Stored entry flagged S_IFLNK with a ZIP64 field declaring uncompressed_size = 2^62 and a zero-byte payload makes extract() fail with:

memory allocation of 4611686018427387904 bytes failed
Aborted (core dumped)          # exit 134

The declared value only needs to exceed the host's address space, not its RAM: Vec::with_capacity() maps address space without touching pages, so resident memory stays flat and the abort happens on the refused reservation itself. Under a ulimit -v cap or a memory-constrained container the threshold drops far enough that a plain 32-bit uncompressed_size with no ZIP64 field suffices.

Applications that extract archives from untrusted input are affected on Unix and Windows targets with default features and no special configuration: upload handling, mail-attachment processing, package and artefact ingestion, backup restore and container-image layer extraction. No confidentiality or integrity property is affected: there is no memory unsafety, no out-of-bounds access, no disclosure and no data corruption.

The fix landed in zip-rs/zip2#984 and shipped in 9.0.0.

For further details see: https://github.com/zip-rs/zip2/security/advisories/GHSA-q7v9-x93c-xqv3

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

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "denial-of-service"
        ],
        "cvss": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "zip",
        "purl": "pkg:cargo/zip"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "9.0.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2026-115909",
    "GHSA-q7v9-x93c-xqv3"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "`ZipArchive::extract()` sizes the symlink-target buffer from the uncompressed\nsize declared in the central directory record, before reading a single byte of\nentry data:\n\n```rust\nlet mut target = Vec::with_capacity(file.size() as usize);\n```\n\nBoth inputs are attacker-controlled. `ZipFile::size()` returns\n`uncompressed_size` verbatim from the central directory, widened to a full `u64`\nby a ZIP64 extended-information extra field, and is never cross-checked against\nthe compressed size, the remaining archive length, or any platform-appropriate\nbound for a symlink target. `ZipFile::is_symlink()` is decided entirely by the\n`S_IFLNK` bit of the external-attributes field.\n\n`Vec::with_capacity()` is infallible: when the reservation is refused it calls\n`handle_alloc_error()` and aborts the process. This is not a Rust panic. It is\nnot caught by `catch_unwind()`, is unaffected by `panic = \"unwind\"`, and is not\ncontained by running the call on a worker thread.\n\nA 112-byte archive is sufficient. One `Stored` entry flagged `S_IFLNK` with a\nZIP64 field declaring `uncompressed_size = 2^62` and a zero-byte payload makes\n`extract()` fail with:\n\n```\nmemory allocation of 4611686018427387904 bytes failed\nAborted (core dumped)          # exit 134\n```\n\nThe declared value only needs to exceed the host\u0027s address space, not its RAM:\n`Vec::with_capacity()` maps address space without touching pages, so resident\nmemory stays flat and the abort happens on the refused reservation itself. Under\na `ulimit -v` cap or a memory-constrained container the threshold drops far\nenough that a plain 32-bit `uncompressed_size` with no ZIP64 field suffices.\n\nApplications that extract archives from untrusted input are affected on Unix and\nWindows targets with default features and no special configuration: upload\nhandling, mail-attachment processing, package and artefact ingestion, backup\nrestore and container-image layer extraction. No confidentiality or integrity\nproperty is affected: there is no memory unsafety, no out-of-bounds access, no\ndisclosure and no data corruption.\n\nThe fix landed in [zip-rs/zip2#984](https://github.com/zip-rs/zip2/pull/984) and\nshipped in 9.0.0.\n\nFor further details see: https://github.com/zip-rs/zip2/security/advisories/GHSA-q7v9-x93c-xqv3",
  "id": "RUSTSEC-2026-0429",
  "modified": "2026-11-02T09:50:37Z",
  "published": "2026-10-22T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/zip"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0429.html"
    }
  ],
  "related": [],
  "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": "zip: `ZipArchive::extract` aborts the process on a symlink entry with a large declared size"
}



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