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Panic on Decoding Short Hybrid Keys

Type: advisorySources: OSV

The deserialization functions `X25519MlKem768Draft00PrivateKey::decode` `X25519MlKem768Draft00PublicKey::decode` and `XWingKemDraft06PublicKey::decode` would panic during an indexing operation when provided an input slice that is shorter than the length of the given key type, i.e. shorter than 2400 bytes in the case of the `X25519MlKem768Draft00` private key and shorter than 1184 bytes in the case of the `X25519MlKem768Draft` and `XWingKemDraft06` public keys. # Impact Applications decoding attacker provided slices into the above mentioned private and public key types could be made to panic. # Mitigation With release of version `0.0.10` of `libcrux-kem` this bug has been fixed and the serialization functions return `InvalidPrivateKey` and `InvalidPublicKey` errors on invalid input buffer lengths. We recommend users upgrade to `libcrux-kem` version `0.0.10`.

Products
libcrux-kem
Affected versions
Not specified
Fixed versions
0.0.10
CVEs
Not specified
Confirmed fixed CVEs
Not specified
Updated in this feed
28 Oct 2026, 03:38 UTC · Revision 1

Source evidence

Panic on Decoding Short Hybrid Keys

core-osv · Original source

Published 24 Aug 2026, 12:00 UTC

The deserialization functions `X25519MlKem768Draft00PrivateKey::decode` `X25519MlKem768Draft00PublicKey::decode` and `XWingKemDraft06PublicKey::decode` would panic during an indexing operation when provided an input slice that is shorter than the length of the given key type, i.e. shorter than 2400 bytes in the case of the `X25519MlKem768Draft00` private key and shorter than 1184 bytes in the case of the `X25519MlKem768Draft` and `XWingKemDraft06` public keys. # Impact Applications decoding attacker provided slices into the above mentioned private and public key types could be made to panic. # Mitigation With release of version `0.0.10` of `libcrux-kem` this bug has been fixed and the serialization functions return `InvalidPrivateKey` and `InvalidPublicKey` errors on invalid input buffer lengths. We recommend users upgrade to `libcrux-kem` version `0.0.10`.

osv:RUSTSEC-2026-0331

libcrux-kem

Fixed versions: 0.0.10

Complete source record
{
  "id": "5c640014dd07338340435c38d192199ae54f5ca1899bd781b3676f229a052058",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2026-0331",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Panic on Decoding Short Hybrid Keys",
    "summary": "The deserialization functions `X25519MlKem768Draft00PrivateKey::decode` `X25519MlKem768Draft00PublicKey::decode` and `XWingKemDraft06PublicKey::decode` would panic during an indexing operation when provided an input slice that is shorter than the length of the given key type, i.e. shorter than 2400 bytes in the case of the `X25519MlKem768Draft00` private key and shorter than 1184 bytes in the case of the `X25519MlKem768Draft` and `XWingKemDraft06` public keys. # Impact Applications decoding attacker provided slices into the above mentioned private and public key types could be made to panic. # Mitigation With release of version `0.0.10` of `libcrux-kem` this bug has been fixed and the serialization functions return `InvalidPrivateKey` and `InvalidPublicKey` errors on invalid input buffer lengths. We recommend users upgrade to `libcrux-kem` version `0.0.10`.",
    "evidence": "osv:RUSTSEC-2026-0331",
    "products": [
      {
        "name": {
          "value": "libcrux-kem",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.0.10",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "RUSTSEC-2026-0331",
      "aliases": [
        "RUSTSEC-2026-0331"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-0"
                },
                {
                  "fixed": "0.0.10"
                }
              ]
            }
          ],
          "package": {
            "name": "libcrux-kem",
            "purl": "pkg:cargo/libcrux-kem",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0331.json",
            "categories": [],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": [
                "libcrux_kem::PrivateKey::decode",
                "libcrux_kem::PublicKey::decode"
              ]
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-07T08:30:02.870588917Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/libcrux-kem",
        "https://rustsec.org/advisories/RUSTSEC-2026-0331.html",
        "https://github.com/celabshq/libcrux/pull/1560"
      ],
      "provider_metadata": {
        "license": "CC0-1.0"
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 94612,
  "published_at": "2026-08-24T12:00:00+00:00"
}