CVE-2026-53525 (CVSS 7.4)

Description

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.

Is your site exposed to CVE-2026-53525?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-208 CWE-208

References

Other References

https://github.com/weechat/weechat/security/advisories/GHSA-vhv8-g2r9-cwcc https://github.com/weechat/weechat/security/advisories/GHSA-vhv8-g2r9-cwcc

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-53525? +

CVE-2026-53525 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53525? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-8794

PaperCut NG/MF contains an observable timing discrepancy in its authentication component. An unauthenticated remote attacker can exploit this vulnerability to …

CVE-2025-29780

Post-Quantum Secure Feldman's Verifiable Secret Sharing provides a Python implementation of Feldman's Verifiable Secret Sharing (VSS) scheme. In versions 0.8.0b2 …

CVE-2025-48995

SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned …

CVE-2025-53940

Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central …

CVE-2025-7071

Padding oracle attack vulnerability in Oberon microsystem AG’s ocrypto library in all versions since 3.1.0 and prior to 3.9.2 allows …

CVE-2025-7383

Padding oracle attack vulnerability in Oberon microsystem AG’s Oberon PSA Crypto library in all versions since 1.0.0 and prior to …

CVE-2026-53525