# CVE-2024-32475: Envoy RELEASE_ASSERT using auto_sni with :authority header > 255 bytes Status: published. Published: 2024-04-18. Updated: 2026-11-05. Envoy is a cloud-native, open source edge and service proxy. When an upstream TLS cluster is used with `auto_sni` enabled, a request containing a `host`/`:authority` header longer than 255 characters triggers an abnormal termination of Envoy process. Envoy does not gracefully handle an error when setting SNI for outbound TLS connection. The error can occur when Envoy attempts to use the `host`/`:authority` header value longer than 255 characters as SNI for outbound TLS connection. SNI length is limited to 255 characters per the standard. Envoy always expects this operation to succeed and abnormally aborts the process when it fails. This vulnerability is fixed in 1.30.1, 1.29.4, 1.28.3, and 1.27.5. ## Remediation - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: security-advisories@github.com) — https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: security-advisories@github.com) — https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: af854a3a-2127-422b-91ae-364da2661108) — https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: af854a3a-2127-422b-91ae-364da2661108) — https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj ## Affected products and versions - envoyproxy / envoy: >= 1.30.0, < 1.30.1 (affected); >= 1.29.0, < 1.29.4 (affected); >= 1.28.0, < 1.28.3 (affected); >= 1.13.0, < 1.27.5 (affected). Source: CNA: GitHub_M - envoyproxy / envoy: ≥ 1.13.0; < 1.27.5 (affected, semver). Source: ADP: CISA-ADP ## NVD configuration conditions Affected CPE matches depend on the following AND/OR and negation conditions: ```json [ { "negate": false, "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.27.5", "versionStartIncluding": "1.13.0", "vulnerable": true }, { "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.28.3", "versionStartIncluding": "1.28.0", "vulnerable": true }, { "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.29.4", "versionStartIncluding": "1.29.0", "vulnerable": true }, { "criteria": "cpe:2.3:a:envoyproxy:envoy:1.30.0:*:*:*:*:*:*:*", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "OR" } ] ``` ## Severity and prioritization - CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M - CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: security-advisories@github.com - CISA KEV: No listing in collected sources - EPSS: 0.68% as of 2026-11-05; percentile 52.51% - SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP - Weaknesses: CWE-253, CWE-617 ## Exploit evidence No exploit evidence in collected sources. This is not proof of no exploitation. ## References - https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj (CNA: GitHub_M; x_refsource_CONFIRM) - https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 (CNA: GitHub_M; x_refsource_MISC) - https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj (ADP: CVE; x_refsource_CONFIRM, x_transferred) - https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 (ADP: CVE; x_refsource_MISC, x_transferred) - https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 (security-advisories@github.com; Patch) - https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj (security-advisories@github.com; Patch, Vendor Advisory) - https://github.com/envoyproxy/envoy/commit/b47fc6648d7c2dfe0093a601d44cb704b7bad382 (af854a3a-2127-422b-91ae-364da2661108; Patch) - https://github.com/envoyproxy/envoy/security/advisories/GHSA-3mh5-6q8v-25wj (af854a3a-2127-422b-91ae-364da2661108; Patch, Vendor Advisory) ## Provenance - CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2024-32475; retrieved 2026-11-05; source updated 2026-11-05 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-32475; retrieved 2026-11-05; source updated 2026-11-05 - FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2024-32475; retrieved 2026-11-05; source updated Not reported Revision: 4b161b8d57ca59642b161f76bf306eb01ed626bc0b2c539fe25d6f852c947f8a Canonical: https://y2.dev/cve/CVE-2024-32475 ## Agent and API access Public CVE pages, Markdown, and JSON are free to read without an account or API key. - Public catalog: https://y2.dev/cve/index.json. 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