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Fencer Vulns
critical 9.3

CVE-2025-54574 in the critical feed json

Squid's URN Handling can lead to Buffer Overflow

published 2025-08-01 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-23392

cvss
9.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
22.1%
EPSS 22.1% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

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.

Patch / fix

  • squid-cache squid 6.4
  • squid Debian 12 5.7-2+deb12u3
  • squid Debian 14, Debian 13 6.5-1

debian advisories DEBIAN-CVE-2025-54574

  • squid Ubuntu 20.04 LTS 4.10-1ubuntu1.12
  • squid Ubuntu 22.04 LTS 5.7-0ubuntu0.22.04.4

ubuntu advisories UBUNTU-CVE-2025-54574

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • squid RHEL 8 7:4.15-7.module+el8.9.0+20806+014d88aa.3
  • libecap RHEL 8 1.0.1-2.module+el8.9.0+19703+a1da7223
  • squid RHEL 9 7:5.5-6.el9_3.2
  • squid RHEL 7 ELS 7:3.5.20-17.el7_9.14
  • squid-sysvinit RHEL 7 ELS 7:3.5.20-17.el7_9.14
  • squid-migration-script RHEL 7 ELS 7:3.5.20-17.el7_9.14
  • squid RHEL 9.0 EUS 7:5.2-1.el9_0.4
  • squid RHEL 8.6 EUS 7:4.15-3.module+el8.6.0+21069+a1561e3d.4

red hat advisories RHSA-2025:14414RHSA-2024:1153RHSA-2024:0771RHSA-2024:0772RHSA-2024:0773RHSA-2024:0397

  • squid AlmaLinux 8 7:4.15-7.module_el8.9.0+3696+b881db49.3
  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+2741+01592ae8
  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+3048+383bc947

almalinux advisories ALSA-2023:7668

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-54574 updated cvss 8.9

squid-cache: Squid Buffer Overflow

  • Red Hat Enterprise Linux 6 squid, squid34
    affected: workaround, no fix planned “Users can disable URN access permissions to mitigate this issue.”
  • Red Hat Enterprise Linux AppStream (v. 8) squid 4.15-7.module+el8.9.0+20806+014d88aa.3, libecap 1.0.1-2.module+el8.9.0+19703+a1da7223
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2023:7668
  • Red Hat Enterprise Linux AppStream (v. 9) squid 5.5-6.el9_3.2
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2023:7465
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0773
  • Red Hat Enterprise Linux AppStream E4S (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0773
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.15-3.module+el8.6.0+21069+a1561e3d.4
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0771
show 7 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.15-6.module+el8.8.0+21068+0ecbc070.3
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0397
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) squid 5.2-1.el9_0.4
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:1153
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) squid 5.5-5.el9_2.3
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0072
  • Red Hat Enterprise Linux AppStream TUS (v. 8.2) squid 4.4-8.module+el8.2.0+21173+22259b09.7, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0772
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+21174+3894a031.6
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2024:0773
  • Red Hat Enterprise Linux Server (v. 7 ELS) squid 3.5.20-17.el7_9.14, squid-migration-script 3.5.20-17.el7_9.14 Red Hat Enterprise Linux Server Optional (v. 7 ELS) squid-sysvinit 3.5.20-17.el7_9.14
    fixed: vendor fix “Users can disable URN access permissions to mitigate this issue.” RHSA-2025:14414
  • Red Hat Enterprise Linux 10 squid
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

22.13% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • squid-cache squid

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.