CVE-2026-53525
CVE-2026-53525 is a high-severity vulnerability with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-208.
Key facts
- Severity: High (CVSS 3.x base score 7.4)
- EPSS exploit prediction: 0% (36th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-208
- Published:
- Last modified:
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.
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.
- How severe is CVE-2026-53525?
- CVE-2026-53525 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
- Is CVE-2026-53525 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-53525?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-53525 published?
- CVE-2026-53525 was published on 2026-08-21.
References
Other CWE-208 vulnerabilities
- CVE-2023-41313 — Critical (CVSS 9.8): The authentication method in Apache Doris versions before 2.0.0 was vulnerable to timing attacks. Users are recommended…
- CVE-2026-16315 — High (CVSS 8.7): OMICRON StationGuard before version 4.10 contains a cryptographic timing side-channel vulnerability in the backend…
- CVE-2024-42512 — High (CVSS 8.6): Vulnerability in the OPC UA .NET Standard Stack before 1.5.374.158 allows an unauthorized attacker to bypass…
- CVE-2026-43606 — High (CVSS 8.5): Observable Timing Discrepancy in the AMD Vitis Libraries ECDSA secp256k1 component could allow attackers with local…
- CVE-2025-53940 — High (CVSS 8.5): Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central…
- CVE-2026-16731 — High (CVSS 8.3): OMICRON StationScout before version 3.05 contains a cryptographic timing side-channel vulnerability in the backend…