{"schema":"threatline.record/2","record":{"id":"GHSA-c8m5-c952-6cm4","aliases":["GHSA-c8m5-c952-6cm4","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.","categories":["Libraries & packages"],"product":"rustls","vendor":"","ecosystem":"rust","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:08:48Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"ecosystem":"rust","name":"rustls"},"range":"< 0.23.46"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:08:48Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"ecosystem":"rust","name":"rustls"},"range":">= 0.24.0-dev.1, < 0.24.0-dev.2"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:15:05.354395696Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"name":"rustls","ecosystem":"crates.io","purl":"pkg:cargo/rustls"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.23.46"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:15:05.354395696Z","fetched_at":"2026-10-27T16:27:21.584480Z","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"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:08:48Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"ecosystem":"rust","name":"rustls"},"version":"0.23.46"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:08:48Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"ecosystem":"rust","name":"rustls"},"version":"0.24.0-dev.2"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:15:05.354395696Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"name":"rustls","ecosystem":"crates.io","purl":"pkg:cargo/rustls"},"version":"0.23.46"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-c8m5-c952-6cm4","source_modified_at":"2026-10-27T16:15:05.354395696Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"name":"rustls","ecosystem":"crates.io","purl":"pkg:cargo/rustls"},"version":"0.24.0-dev.2"}],"cvss":4,"severity":"Medium","kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-27T16:08:47Z","modified_at":"2026-10-27T16:15:05.354395696Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","fetched_at":"2026-10-27T16:27:21.584480Z","source_modified_at":"2026-10-27T16:08:48Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-c8m5-c952-6cm4","fetched_at":"2026-10-27T16:27:21.584480Z","source_modified_at":"2026-10-27T16:15:05.354395696Z"}],"sources":["GitHub Advisory Database","OSV"],"references":[{"url":"https://github.com/rustls/rustls/security/advisories/GHSA-c8m5-c952-6cm4","source":"GitHub Advisory Database"},{"url":"https://github.com/rustls/rustls/pull/3299","source":"GitHub Advisory Database"},{"url":"https://github.com/rustls/rustls/pull/3354","source":"GitHub Advisory Database"},{"url":"https://github.com/rustls/rustls/commit/dcdb9464d376f45f42a94a5f837cda1506449f23","source":"GitHub Advisory Database"},{"url":"https://github.com/rustls/rustls/commit/f5f7bf5078a7edcbd81a9e82a97f2bd14dc1c855","source":"GitHub Advisory Database"},{"url":"https://github.com/rustls/rustls/releases/tag/v/0.23.46","source":"GitHub Advisory Database"},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0346.html","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-c8m5-c952-6cm4","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-27T16:15:05.354395696Z","content_hash":"7d86aa9229a4002923b979119b71336fad6c92d240fd317c9e4f1ee6bcf7661b"}}