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TI-2023-25207 Aliases CVE-2023-46724

SQUID-2023:4 Denial of Service in SSL Certificate validation

Priority MEDIUM 48CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service, Spoofing
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 16 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-125, CWE-295 and the CVSS impact.

Summary

Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions 3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of Service attack against SSL Certificate validation. This problem allows a remote server to perform Denial of Service against Squid Proxy by initiating a TLS Handshake with a specially crafted SSL Certificate in a server certificate chain. This attack is limited to HTTPS and SSL-Bump. This bug is fixed in Squid version 6.4. In addition, patches addressing this problem for the stable releases can be found in Squid's patch archives. Those who you use a prepackaged version of Squid should refer to the package vendor for availability information on updated packages.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.02807 86th percentileScored 2026-11-07
Fix Partial squid (squid-cache): 6.4Red Hat: 9 advisoriesRed Hat: 16 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

VendorProductAffected versionsFixed inStatusSource
squid-cachesquid3.3.0.1 to before 6.46.4Patch availableCNA
  • squid Vendorsquid-cache Affected 3.3.0.1 to before 6.4 Fixed in 6.4 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*3.3.0.1 to before 6.4Vulnerablesquid-cache
  • cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* Versions 3.3.0.1 to before 6.4 Vulnerable ·squid-cache

Remediation

  • Fix · CNA squid (squid-cache) Fixed in 6.4

Red Hat 9 advisories

  • RHSA-2024:1787 Released 2024-04-11 · Red Hat rating Important
    squid security update
    • Red Hat Enterprise Linux Server (v. 7) squid-7:3.5.20-17.el7_9.10, squid-migration-script-7:3.5.20-17.el7_9.10
    • Red Hat Enterprise Linux Server Optional (v. 7) squid-sysvinit-7:3.5.20-17.el7_9.10
    • Red Hat Enterprise Linux Workstation (v. 7) squid-7:3.5.20-17.el7_9.10, squid-migration-script-7:3.5.20-17.el7_9.10
    • Red Hat Enterprise Linux Workstation Optional (v. 7) squid-sysvinit-7:3.5.20-17.el7_9.10
  • RHSA-2024:1153 Released 2024-03-05 · Red Hat rating Important
    squid 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 Important
    squid: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 Important
    squid: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 Important
    squid: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 Important
    squid: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-2024:0071 Released 2024-01-08 · Red Hat rating Important
    squid security update
    • Red Hat Enterprise Linux AppStream (v. 9) squid-7:5.5-6.el9_3.5
  • RHSA-2024:0072 Released 2024-01-08 · Red Hat rating Important
    squid security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.2) squid-7:5.5-5.el9_2.3
  • RHSA-2024:0046 Released 2024-01-03 · Red Hat rating Important
    squid: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

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2024:0046
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2024:0071
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)Fixed RHSA-2024:1787
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2024:1787
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2024:1787
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2024:1787

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-46724
  2. 2026-11-02 EPSS moved to the 50th–90th percentile

References

Patch 3

Advisory 1

Other 3

  • 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
See all 110 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences