Squid's URN Handling can lead to Buffer Overflow
Priority HIGH 68CWE-122Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 14 fixed, 1 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.22133 97th percentileScored 2026-11-07
Fix Partial squid (squid-cache): 6.4Red Hat: 9 advisoriesRed Hat: 14 fixed, 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| squid-cache | squid | before 6.4 | 6.4 | Patch available | CNA |
- squid Vendorsquid-cache Affected before 6.4 Fixed in 6.4 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* | before 6.4 | Vulnerable | squid-cache |
- cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* Versions before 6.4 Vulnerable ·squid-cache
Remediation
- Fix · CNA squid (squid-cache) Fixed in 6.4
Red Hat 9 advisories
- RHSA-2025:14414 Released 2025-08-25 · Red Hat rating Importantsquid security update
- Red Hat Enterprise Linux Server (v. 7 ELS) squid-7:3.5.20-17.el7_9.14, squid-migration-script-7:3.5.20-17.el7_9.14
- Red Hat Enterprise Linux Server Optional (v. 7 ELS) squid-sysvinit-7:3.5.20-17.el7_9.14
- RHSA-2024:1153 Released 2024-03-05 · Red Hat rating Importantsquid security update
- Red Hat Enterprise Linux AppStream EUS (v.9.0) squid-7:5.2-1.el9_0.4
- RHSA-2024:0771 Released 2024-02-12 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream EUS (v.8.6) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.aarch64::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.s390x::squid:4 +11
Show 6 more Red Hat advisories
- RHSA-2024:0773 Released 2024-02-12 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4, libecap-devel-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +2
- Red Hat Enterprise Linux AppStream E4S (v.8.4) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +5
- Red Hat Enterprise Linux AppStream TUS (v.8.4) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4, libecap-devel-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +2
- RHSA-2024:0772 Released 2024-02-12 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream AUS (v. 8.2) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4, libecap-devel-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +2
- Red Hat Enterprise Linux AppStream E4S (v. 8.2) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +5
- Red Hat Enterprise Linux AppStream TUS (v. 8.2) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.src::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4, libecap-devel-1.0.1-2.module+el8.1.0+4044+36416a77.x86_64::squid:4 +2
- RHSA-2024:0397 Released 2024-01-24 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream EUS (v.8.8) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.aarch64::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.s390x::squid:4 +11
- RHSA-2024:0072 Released 2024-01-08 · Red Hat rating Importantsquid security update
- Red Hat Enterprise Linux AppStream EUS (v.9.2) squid-7:5.5-5.el9_2.3
- RHSA-2023:7668 Released 2023-12-06 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream (v. 8) libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.aarch64::squid:4, libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.ppc64le::squid:4, libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.s390x::squid:4 +11
- RHSA-2023:7465 Released 2023-11-22 · Red Hat rating Importantsquid security update
- Red Hat Enterprise Linux AppStream (v. 9) squid-7:5.5-6.el9_3.2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2023:7668 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2023:7465 |
| Red Hat Enterprise Linux AppStream AUS (v. 8.2) | Fixed | RHSA-2024:0772 |
| Red Hat Enterprise Linux AppStream AUS (v.8.4) | Fixed | RHSA-2024:0773 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.2) | Fixed | RHSA-2024:0772 |
| Red Hat Enterprise Linux AppStream E4S (v.8.4) | Fixed | RHSA-2024:0773 |
| Red Hat Enterprise Linux AppStream EUS (v.8.6) | Fixed | RHSA-2024:0771 |
| Red Hat Enterprise Linux AppStream EUS (v.8.8) | Fixed | RHSA-2024:0397 |
| Red Hat Enterprise Linux AppStream EUS (v.9.0) | Fixed | RHSA-2024:1153 |
| Red Hat Enterprise Linux AppStream EUS (v.9.2) | Fixed | RHSA-2024:0072 |
| Red Hat Enterprise Linux AppStream TUS (v. 8.2) | Fixed | RHSA-2024:0772 |
| Red Hat Enterprise Linux AppStream TUS (v.8.4) | Fixed | RHSA-2024:0773 |
| Red Hat Enterprise Linux Server (v. 7 ELS) | Fixed | RHSA-2025:14414 |
| Red Hat Enterprise Linux Server Optional (v. 7 ELS) | Fixed | RHSA-2025:14414 |
Not affected: 1 product
- Red Hat Enterprise Linux 10
Timeline
- 2026-10-02 Threatist record created from CVE-2025-54574
References
More squid-cache Squid vulnerabilities
- TI-2025-38486 Squid vulnerable to information disclosure via authentication credential leakage in error handling CVSS 3.1CRITICAL 10.0
- TI-2024-16845 Denial of Service in HTTP Header parser in squid proxy CVSS 3.1HIGH 7.5
- TI-2024-16566 SQUID-2024:1 Denial of Service in HTTP Chunked Decoding CVSS 3.1HIGH 8.6
- TI-2023-26921 Denial of Service in HTTP Message Processing in Squid CVSS 3.1HIGH 8.6
- TI-2023-27496 SQUID-2023:10 Denial of Service in HTTP Request parsing CVSS 3.1HIGH 8.6
- TI-2023-25306 Squid: denial of service in http digest authentication CVSS 3.1HIGH 8.6
Sources
- CVE-2025-54574 · CVE Program
- CVE-2025-54574 · NVD
- FIRST EPSS
- CVE-2025-54574 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences