{"id":"CVE-2025-24898","aliases":["RUSTSEC-2025-0004","GHSA-rpmj-rpgj-qmpm"],"title":"ssl::select_next_proto use after free","summary":"ssl::select_next_proto use after free","severity":"none","vendor":"openssl","product":"openssl","ecosystem":"rust","affected":["openssl >= 0.0.0-0, < 0.10.70"],"patched":["openssl 0.10.70"],"published":"2025-02-02","updated":"2026-10-12","sourceUpdated":"2026-10-12T18:00:12.406916247Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/RUSTSEC-2025-0004","references":[{"url":"https://crates.io/crates/openssl"},{"url":"https://rustsec.org/advisories/RUSTSEC-2025-0004.html"},{"url":"https://github.com/sfackler/rust-openssl/pull/2360"},{"url":"https://github.com/sfackler/rust-openssl/pull/2360"}],"tags":["osv","rust"],"epss":0.0068,"epssPercentile":0.51068,"ingestedAt":"2026-10-13T11:45:30.176Z","slug":"CVE-2025-24898","body":"## Overview\n\nIn `openssl` versions before `0.10.70`, `ssl::select_next_proto` can return a slice pointing into the `server` argument's buffer but with a lifetime bound to the `client` argument. In situations where the `server` buffer's lifetime is shorter than the `client` buffer's, this can cause a use after free. This could cause the server to crash or to return arbitrary memory contents to the client.\n\n`openssl` 0.10.70 fixes the signature of `ssl::select_next_proto` to properly constrain the output buffer's lifetime to that of both input buffers.\n\nIn standard usage of `ssl::select_next_proto` in the callback passed to `SslContextBuilder::set_alpn_select_callback`, code is only affected if the `server` buffer is constructed *within* the callback. For example:\n\nNot vulnerable - the server buffer has a `'static` lifetime:\n```rust\nbuilder.set_alpn_select_callback(|_, client_protos| {\n    ssl::select_next_proto(b\"\\x02h2\", client_protos).ok_or_else(AlpnError::NOACK)\n});\n```\n\nNot vulnerable - the server buffer outlives the handshake:\n```rust\nlet server_protos = b\"\\x02h2\".to_vec();\nbuilder.set_alpn_select_callback(|_, client_protos| {\n    ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK)\n});\n```\n\nVulnerable - the server buffer is freed when the callback returns:\n```rust\nbuilder.set_alpn_select_callback(|_, client_protos| {\n    let server_protos = b\"\\x02h2\".to_vec();\n    ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK)\n});\n```\n\n## Affected packages\n\n- `openssl >= 0.0.0-0, < 0.10.70`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `openssl 0.10.70`","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}