Vulnerability in Weechat

CVE-2026-53525

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (35.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-53525: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002

Affected products

  • Weechat — versions >= 0.3.4, < 4.9.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-53525?
CVE-2026-53525 is a high-severity vulnerability in Weechat, classified under CWE-208. CVSS score: 7.4/10. Published 2026-08-21.
How severe is CVE-2026-53525?
High severity. CVSS v3 base score is 7.4 out of 10.