Bug 2514546 - CVE-2026-29035 civetweb: CivetWeb: Arbitrary code execution via crafted WebSocket frames [epel-all]
Summary: CVE-2026-29035 civetweb: CivetWeb: Arbitrary code execution via crafted WebSo...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: civetweb
Version: epel10
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Mattias Ellert
QA Contact:
URL:
Whiteboard: {"flaws": ["c5690dbf-c738-417b-8fae-d...
Depends On:
Blocks: CVE-2026-29035
TreeView+ depends on / blocked
 
Reported: 2026-08-12 10:15 UTC by Ganesh
Modified: 2026-08-28 05:40 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2026-08-28 05:40:13 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Ganesh 2026-08-12 10:15:22 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

CivetWeb (commit 4a4f0c95) contains a heap and stack buffer overflow vulnerability in the read_websocket() function that allows unauthenticated remote attackers to corrupt memory by sending compressed WebSocket frames when both USE_ZLIB and MG_EXPERIMENTAL_INTERFACES are defined. Attackers can negotiate permessage-deflate during the WebSocket handshake and send a crafted frame with the RSV1 bit set, causing the server to write a 4-byte zlib sync trailer out-of-bounds past the allocated buffer, leading to heap metadata corruption, denial of service, or potential code execution.

Comment 1 Mattias Ellert 2026-08-28 05:40:13 UTC
(In reply to Ganesh from comment #0)
> when both USE_ZLIB and MG_EXPERIMENTAL_INTERFACES are defined.

The EPEL build of civetweb defines USE_ZLIB but not MG_EXPERIMENTAL_INTERFACES.
It is therefore not affected by this CVE.


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