Out-of-bounds Write Affecting civetweb package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.61% (47th percentile)

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  • Snyk IDSNYK-DEBIAN13-CIVETWEB-18860556
  • published16 Aug 2026
  • disclosed11 Aug 2026

Introduced: 11 Aug 2026

CVE-2026-29035  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

There is no fixed version for Debian:13 civetweb.

NVD Description

Note: Versions mentioned in the description apply only to the upstream civetweb package and not the civetweb package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1