CVE-2025-54574

Squid's URN Handling can lead to Buffer Overflow

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.

Affected

squid-cache · squid

CVSS v3.1 NVD

9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 GITHUB

9.3 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H

EPSS

23.51% chance of exploitation in the next 30 days, 98th percentile

Published

2025-08-01

Updated

2025-11-05

Proof-of-concept exploits (1)

• gmh5225/Blackash-CVE-2025-545740★ · 2025-08-04

Security advisories

• squid-cache/squid/security/advisories/GHSA-w4gv-vw3f-29g3
• squid-cache/squid/commit/a27bf4b84da23594150c7a86a23435df0b35b988

References

• CVE Record
• NVD entry

Related

• CVE-2003-0358
• CVE-2015-2291
• CVE-2020-36603
• CVE-2021-42205
• CVE-2022-24716
• CVE-2022-34683