Buffer overflow in Squid-Cache Squid
CVE-2025-54574
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.227 (97.7th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.229 · newest: 0.227 · change: -0.002
Affected products
- Squid-Cache Squid — versions < 6.4
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/squid-cache/squid/security/advisories/GHSA-w4gv-vw3f-29g3 (Patch, Mitigation, Vendor Advisory)
- github.com/squid-cache/squid/commit/a27bf4b84da23594150c7a86a23435df0b35b988 (Patch)
- github.com/squid-cache/squid/releases/tag/SQUID_6_4 (Release Notes)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-54574?
- CVE-2025-54574 is a critical-severity vulnerability in Squid-Cache Squid, classified under Heap-based Buffer Overflow. CVSS score: 9.3/10. Published 2025-08-01.
- How severe is CVE-2025-54574?
- Critical severity. CVSS v3 base score is 9.3 out of 10.
- Is CVE-2025-54574 known to be exploited?
- 7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.