{"schema_version":"1.9.2","id":"GHSA-c8m5-c952-6cm4","published":"2026-10-27T16:08:47Z","modified":"2026-10-27T16:15:05.354395696Z","aliases":["RUSTSEC-2026-0346"],"summary":"Rustls: Session Debug formatting exposes TLS master secrets and resumption PSKs","details":"### Summary\n\nFormatting a client session value with Debug exposes its TLS 1.2 master secret or TLS 1.3 resumption PSK. A custom session store that logs these values can disclose keys to readers of the logs. Ordinary connection and built-in cache diagnostics remain redacted, and the session-store interface already warns that its values are sensitive.\n\n### Details\n\nDerived formatters traverse the session's secret-bearing fields. This conflicts with the project's explicit [key-material redaction policy](https://github.com/rustls/rustls/blob/99f2358cae2954837dbb866faf6727de75489ab9/SECURITY.md#boundary-public-api).\n\n### Proof of concept\n\nCustom `ClientSessionStore` implementations could leak secret data by using the provided `Tls12ClientSessionValue` or `Tls13ClientSessionValue` in a way that triggers its implementation of the `Debug` trait.\n\n### Impact\n\nSuch store implementations could leak the master secret for the TLS connection.\n\n### Acknowledgement\nThanks to OpenAI [OutboundDisclosures@openai.com](mailto:OutboundDisclosures@openai.com) for the disclosure.","affected":[{"package":{"name":"rustls","ecosystem":"crates.io","purl":"pkg:cargo/rustls"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.23.46"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-c8m5-c952-6cm4/GHSA-c8m5-c952-6cm4.json"}},{"package":{"name":"rustls","ecosystem":"crates.io","purl":"pkg:cargo/rustls"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.24.0-dev.1"},{"fixed":"0.24.0-dev.2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-c8m5-c952-6cm4/GHSA-c8m5-c952-6cm4.json"}}],"references":[{"type":"WEB","url":"https://github.com/rustls/rustls/security/advisories/GHSA-c8m5-c952-6cm4"},{"type":"WEB","url":"https://github.com/rustls/rustls/pull/3299"},{"type":"WEB","url":"https://github.com/rustls/rustls/pull/3354"},{"type":"WEB","url":"https://github.com/rustls/rustls/commit/dcdb9464d376f45f42a94a5f837cda1506449f23"},{"type":"WEB","url":"https://github.com/rustls/rustls/commit/f5f7bf5078a7edcbd81a9e82a97f2bd14dc1c855"},{"type":"PACKAGE","url":"https://github.com/rustls/rustls"},{"type":"WEB","url":"https://github.com/rustls/rustls/releases/tag/v/0.23.46"},{"type":"WEB","url":"https://rustsec.org/advisories/RUSTSEC-2026-0346.html"}],"database_specific":{"cwe_ids":["CWE-212"],"github_reviewed":true,"github_reviewed_at":"2026-10-27T16:08:47Z","nvd_published_at":null,"severity":"MODERATE"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N"}]}