Nghttp2: community verdicts
2 notable / known-exploited Nghttp2 CVEs the community has triaged.
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| Year published | CVEs | In CISA KEV |
|---|---|---|
| 2023 | 1 | 1 |
| 2024 | 0 | 0 |
| 2025 | 0 | 0 |
| 2026 | 1 | 0 |
Exploitation first, with newly exploited CVEs rising above old ones
- CVE-2023-44487HIGH 7.5KEVEPSS 100%
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
- CVE-2026-27135HIGH 7.5Real · low riskEPSS 1%
nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. Prior to version 1.68.1, the nghttp2 library stops reading the incoming data when user facing public API `nghttp2_session_terminate_session` or `nghttp2_session_terminate_session2` is called by the application. They might be called internally by the library when it detects the situation that is subject to connection error. Due to the missing internal state validation, the library keeps reading the rest of the data after one of those APIs is called. Then receiving a malformed frame that causes FRAME_SIZE_ERROR causes assertion failure. nghttp2 v1.68.1 adds missing state validation to avoid assertion failure. No known workarounds are available.