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Fencer Intel
high 7.4

CVE-2026-53525 json

WeeChat has Non-Constant-Time Password Hash Comparison in Relay Authentication

published 5mo ago modified 28d ago also EUVD-2026-64186 , GHSA-vhv8-g2r9-cwcc

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository weechat/weechat. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp and strcmp) to verify password hashes and plaintext passwords. An attacker can exploit timing differences to extract the server-computed hash character by character, then authenticate using the correct hash without knowing the password. Version 4.9.1 fixes the issue.

Patch / fix

  • weechat weechat 4.9.1
  • weechat Debian 14 4.9.3-1

debian advisories DEBIAN-CVE-2026-53525

  • weechat openSUSE Leap 16.0 4.10.0-bp160.1.1
  • weechat openSUSE Tumbleweed 4.10.0-1.1

opensuse advisories openSUSE-SU-2026:21615-1openSUSE-SU-2026:11481-1

Is CVE-2026-53525 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-53525 updated cvss 7.4

weechat: WeeChat: Authentication bypass due to non-constant-time password hash comparison

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/weechat/weechat/security/advisories/GHSA-vhv8-g2r9-cwcc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected products

  • weechat weechat

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy

References

Sources

Fencer Intel 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.

The maintainers of weechat/weechat published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.