CyberSecBulletin

Nghttp2 vulnerabilities

We track 3 vulnerabilities in Nghttp2 products. 3 are rated high or critical, and 1 has been exploited in real attacks. The most recent was published on March 18, 2026.

3vulnerabilities
0critical
3high
1exploited
7.5average CVSS score

Latest Nghttp2 vulnerabilities

  • 7.5 High severity

    nghttp2: Reachable Assertion

    CVE-2026-27135Nghttp2

    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`

  • 7.5 High severity

    HTTP/2 Rapid Reset Attack Exploited

    CVE-2023-44487IETFEPSS 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.

  • 7.5 High severity

    envoy: Incomplete Cleanup

    CVE-2023-35945EnvoyproxyEPSS 1.65%

    Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving `RST_STREAM` immediately followed by the `GOAWAY` frames from an upstream server. In nghttp2, cleanup of pe