What is CVE-2026-27135?

CVE-2026-27135 is a high-severity vulnerability in Nghttp2, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2026-03-18.

How severe is CVE-2026-27135?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Nghttp2

CVE-2026-27135

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_sessio…

EPSS: 0.000 (9.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Nghttp2 — versions < 1.68.1

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-27135?: CVE-2026-27135 is a high-severity vulnerability in Nghttp2, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2026-03-18.
How severe is CVE-2026-27135?: High severity. CVSS v3 base score is 7.5 out of 10.