`Debug` impls for client session values expose TLS secrets

{
  "id": "dd0a630c104c70076ff01a1ed295b34572c2f61d4c75d2545238ad00f7e704c5",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2026-0346",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "`Debug` impls for client session values expose TLS secrets",
    "summary": "The `Debug` implementations of `Tls12ClientSessionValue` and `Tls13ClientSessionValue` were derived, and so included the TLS 1.2 master secret or TLS 1.3 resumption PSK in their output. Custom `ClientSessionStore` implementations that format these values with `Debug` (for example, when logging) could disclose these secrets to readers of the logs. This conflicts with rustls's [key-material redaction policy](https://github.com/rustls/rustls/blob/99f2358cae2954837dbb866faf6727de75489ab9/SECURITY.md#boundary-public-api). Ordinary connection and built-in session cache `Debug` output is redacted and is not affected.",
    "evidence": "osv:RUSTSEC-2026-0346",
    "products": [
      {
        "name": {
          "value": "rustls",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.23.46",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "RUSTSEC-2026-0346",
      "aliases": [
        "GHSA-c8m5-c952-6cm4",
        "RUSTSEC-2026-0346"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.21.0"
                },
                {
                  "fixed": "0.23.46"
                }
              ]
            }
          ],
          "package": {
            "name": "rustls",
            "purl": "pkg:cargo/rustls",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": "CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N",
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0346.json",
            "categories": [
              "crypto-failure"
            ],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": []
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-14T13:30:02.480694744Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/rustls",
        "https://rustsec.org/advisories/RUSTSEC-2026-0346.html",
        "https://github.com/rustls/rustls/pull/3299"
      ],
      "provider_metadata": {
        "license": "CC0-1.0"
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 316314,
  "published_at": "2026-10-14T12:00:00+00:00"
}