CVE-2025-54574
In versions 6.3 and below, Squid is vulnerable to a heap buffer overflow and possible remote code execution attack when processing URN due to incorrect buffer management.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 24.0%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
Squid is a caching proxy for the Web. In versions 6.3 and below, Squid is vulnerable to a heap buffer overflow and possible remote code execution attack when processing URN due to incorrect buffer management. This has been fixed in version 6.4. To work around this issue, disable URN access permissions.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 23.96% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-122, CWE-787
- Affected
- squid-cache/squid
- Source
- security-advisories@github.com
EPSS moved from 23.7% on 2 October 2026 to 24.0% on 1 November 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- https://github.com/squid-cache/squid/commit/a27bf4b84da23594150c7a86a23435df0b35b988Patch
- https://github.com/squid-cache/squid/releases/tag/SQUID_6_4Release Notes
- https://github.com/squid-cache/squid/security/advisories/GHSA-w4gv-vw3f-29g3Mitigation, Patch, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2025/11/05/5
- https://lists.debian.org/debian-lts-announce/2025/09/msg00027.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.