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Fencer Vulns
medium 6.5

CVE-2026-33515 json

Squid has issues in ICP message handling

published 2026-03-26 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-16067

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

Squid is a caching proxy for the Web. Prior to version 7.5, due to improper input validation, Squid is vulnerable to out of bounds read when handling ICP traffic. This problem allows a remote attacker to receive small amounts of memory potentially containing sensitive information when responding with errors to invalid ICP requests. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem cannot be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch.

Patch / fix

  • squid-cache squid 7.5
  • squid Debian 12 5.7-2+deb12u6
  • squid Debian 13 6.13-2+deb13u2
  • squid Debian 14 7.5-1

debian advisories DEBIAN-CVE-2026-33515

  • squid Ubuntu 22.04 LTS 5.9-0ubuntu0.22.04.5
  • squid Ubuntu 24.04 LTS 6.14-0ubuntu0.24.04.2
  • squid Ubuntu 25.10 6.14-0ubuntu0.25.10.2
  • squid Ubuntu Pro 20.04 LTS 4.10-1ubuntu1.13+esm3
  • squid3 Ubuntu Pro 16.04 LTS 3.5.12-1ubuntu7.16+esm7
  • squid3 Ubuntu Pro 18.04 LTS 3.5.27-1ubuntu1.14+esm6

ubuntu advisories UBUNTU-CVE-2026-33515

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 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 5.7-150400.3.41.1
  • squid SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Server Applications 15 SP7 6.14-150600.3.20.1
  • squid SLES for SAP applications 16.0, SLES 16.0 6.14-160000.1.1

suse advisories SUSE-SU-2026:4909-1SUSE-SU-2026:4621-1SUSE-SU-2026:24224-1

  • squid openSUSE Leap 16.0 6.14-160000.1.1
  • squid openSUSE Tumbleweed 7.7-2.1

opensuse advisories openSUSE-SU-2026:22080-1openSUSE-SU-2026:11937-1

  • squid Azure Linux 3.0 6.13-4

azure linux advisories AZL-80765

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-33515 updated cvss 5.3

Squid: Squid: Information disclosure via improper input validation in ICP traffic

  • Red Hat Enterprise Linux 6 squid, squid34
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script Red Hat Enterprise Linux 8 squid, libecap Red Hat Enterprise Linux 9 squid Red Hat Enterprise Linux 10 squid
    affected: workaround, no fix available “Fix deferred”

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
7 mo ago

Exploit prediction

1.06% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

  • squid-cache squid

Classification

Weakness
  • CWE-125 Out-of-bounds Read
  • CWE-1289 Improper Validation of Unsafe Equivalence in Input

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.