WeeChat before 3.2.1 allows remote attackers to cause a denial of service (crash) via a crafted WebSocket frame that trigger an out-of-boun…

published 2021-09-05 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27692

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.6%; EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits: 0; none known

WeeChat before 3.2.1 allows remote attackers to cause a denial of service (crash) via a crafted WebSocket frame that trigger an out-of-bounds read in plugins/relay/relay-websocket.c in the Relay plugin.

Patch / fix

fixed in 1 distros 5 links 2

weechat weechat 3.2.1

debian ubuntu opensuse alpine arch linux

weechat Debian 14, Debian 13, Debian 12 3.2.1-1

debian advisories DEBIAN-CVE-2021-40516

weechat Ubuntu Pro 16.04 LTS 1.4-2ubuntu0.1+esm1
weechat Ubuntu Pro 18.04 LTS 1.9.1-1ubuntu1+esm1
weechat Ubuntu Pro 20.04 LTS 2.8-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-40516

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

weechat Package Hub 15 SP3, openSUSE Leap 15.3 3.2.1-bp153.2.3.1

opensuse advisories openSUSE-SU-2022:0083-1

weechat Alpine 3.15 3.5-r0

alpine advisories ALPINE-CVE-2021-40516

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

weechat Arch Linux 3.2.1-1

arch linux advisories AVG-2365

github.com/weechat/weechat@8b1331f commit
weechat.org/doc/security/ advisory

Exploit prediction

1.59% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

CWE-125 Out-of-bounds Read

References

github.com /weechat/weechat/commit/8b1331f98de1714bae15a9ca2e2b393ba49d735b
patch, third-party-advisory
weechat.org /doc/security/
patch, vendor-advisory
lists.debian.org /debian-lts-announce/2021/09/msg00018.html
mailing-list, third-party-advisory

Sources

CVE List CVE-2021-40516
NVD CVE-2021-40516

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary