Vulnerability details
CVE-2026-124040
CivetWeb CivetWeb
CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State
CVSS 4.0
9.2Critical
Official description
CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free vulnerability in handle_http2() that retains freed :method and :path pointers. Unauthenticated remote attackers can send a later HEADERS frame omitting these pseudo-headers to influence request method or path seen by access rules, or crash the server.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.2Critical | 4.0 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 8.1High | 3.1 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| CivetWeb | CivetWeb | v ≤ 1.16 | CVEProject cvelistV5 (CNA) |
References and advisories
4- https://github.com/civetweb/civetweb/issues/1379 issue-tracking
- https://github.com/civetweb/civetweb product
- https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581 technical-description
- https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state third-party-advisory
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Details
- Published
- 2026-11-06
- Last updated
- 2026-11-06
- State
- Published
- Assigner (CNA)
- VulnCheck
- Kolun priority
- 25 · Low
Exploit prediction (EPSS)
0.51%
Probability of exploitation in 30 days
44%
Percentile (among all CVEs)
Weaknesses (CWE)
- CWE-416Use After Free