HIGHCVSS v3.1 8.1Vulnerability
CVE-2026-55368
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.
Properties
- Severity
- HIGH
- Nvd fetched at
- 2026-11-05T01:47:04.832199+00:00
- Cvss severity
- HIGH
- Cvss score
- 8.1
- Retrieved at
- 2026-11-05T01:47:49+00:00
- Score
- 8.1
- Cvss version
- 3.1
- Last source
- NVD
- Cve id
- CVE-2026-55368
- Cvss vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- First seen by Signal
- 2026-11-05T01:42:37+00:00
- Name
- CVE-2026-55368
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published at
- 2026-11-04T22:18:06.343
- Last modified
- 2026-11-04T22:18:06.343
Related Entities (1)
HAS_WEAKNESS (1)
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