UBUNTU-CVE-2026-55368
Dashboard / Vulnerabilities / UBUNTU-CVE-2026-55368
Summary:
Details: h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 48b7ae12107fd2b118e4641da49599e9aac8edd8, H2O's access-log formatter could write past its log-line buffer when an affected custom access-log format was configured. The allocation errors affected %{error}x, %q when the query string was empty, and numeric elements whose temporary terminating NUL reached the end of the buffer. A matching request could crash the server, while the effect of the one-byte NUL overwrite beyond a crash was not established. This vulnerability is fixed with commit 48b7ae12107fd2b118e4641da49599e9aac8edd8.
References: https://ubuntu.com/security/CVE-2026-55368, https://www.cve.org/CVERecord?id=CVE-2026-55368, https://github.com/h2o/h2o/security/advisories/GHSA-m998-r5ww-rqjf, https://github.com/h2o/h2o/pull/3757, https://github.com/h2o/h2o/commit/48b7ae12107fd2b118e4641da49599e9aac8edd8
Affected packages
Package
Name: h2o
Purl: pkg:deb/ubuntu/h2o?arch=source&distro=esm-apps%2Fbionic
Affected ranges
Type: ECOSYSTEM
Events:
