CVE-2026-124040

CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State

Published Nov 6, 2026 CVSS 4.0 · 9.2 Critical EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State
First Time appeared Civetweb Project
Civetweb Project civetweb
Weaknesses CWE-416
CPEs cpe:2.3:a:civetweb_project:civetweb:*:*:*:*:*:*:*:*
Vendors & Products Civetweb Project
Civetweb Project civetweb
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 11, 2026, 3:24 AM
Reserved
Nov 6, 2026, 7:11 PM
Status
Deferred
Published
Nov 6, 2026, 8:17 PM
Modified
Nov 11, 2026, 5:19 AM