CVE-2026-124040
CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-416 |
| Vendor | civetweb |
| Product | civetweb |
| Published | Nov 6, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
civetweb / civetweb
0 ≤ 1.16
References
github.com: https://github.com/civetweb/civetweb/issues/1379 github.com: https://github.com/civetweb/civetweb github.com: https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581 vulncheck.com: https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state
Credits
PuH4ck3rX 🔍 Lee Keon-Hyeong