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TI-2018-15687 Aliases CVE-2018-1000027GHSA-hwhj-rr4w-2xmm

The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23…

Priority MEDIUM 47CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 4 fixed, 1 without a fix

Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.

Summary

The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23 contains a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can result in Denial of Service to all clients of the proxy. This attack appear to be exploitable via Remote HTTP server responding with an X-Forwarded-For header to certain types of HTTP request. This vulnerability appears to have been fixed in 4.0.23 and later.

Why it matters now

EPSS 0.12912 96th percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 4 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*before 4.0.23Vulnerablesquid-cache
cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*7.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*8.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*14.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*16.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*17.10VulnerableCanonical
  • cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* Versions before 4.0.23 Vulnerable ·squid-cache
  • cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* Versions 14.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:* Versions 17.10 Vulnerable ·Canonical

Remediation

Red Hat 1 advisory

  • RHSA-2020:1068 Released 2020-03-31 · Red Hat rating Moderate
    squid security and bug fix update
    • Red Hat Enterprise Linux Server (v. 7) squid-7:3.5.20-15.el7, squid-migration-script-7:3.5.20-15.el7
    • Red Hat Enterprise Linux Server Optional (v. 7) squid-sysvinit-7:3.5.20-15.el7
    • Red Hat Enterprise Linux Workstation (v. 7) squid-7:3.5.20-15.el7, squid-migration-script-7:3.5.20-15.el7
    • Red Hat Enterprise Linux Workstation Optional (v. 7) squid-sysvinit-7:3.5.20-15.el7

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:1068
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2020:1068
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:1068
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2020:1068
Not affected: 2 products
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2018-1000027
  2. 2026-10-03 Alias added: GHSA-hwhj-rr4w-2xmm

References

Patch 3

Advisory 6

Sources

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