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Fencer Intel
medium 6.8

CVE-2015-5400 json

Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to…

published 11y ago modified 4mo ago also EUVD-2015-5356

cvss
6.8
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
20.8%
EPSS 20.8% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.

Patch / fix

  • squid Debian 14, Debian 13, Debian 12 4.1-1

debian advisories DEBIAN-CVE-2015-5400

  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu6

ubuntu advisories UBUNTU-CVE-2015-5400

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

  • squid3 SLES for SAP 11 SP4, SLES 11 SP4 3.1.23-8.16.30.1
  • squid SLES for SAP 12 SP1, SLES 12 SP1 3.3.14-20.2

suse advisories SUSE-SU-2016:2089-1SUSE-SU-2016:2008-1

  • squid openSUSE Tumbleweed 3.5.22-1.1

opensuse advisories openSUSE-SU-2024:10307-1

Is CVE-2015-5400 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2015-5400 updated cvss 2.3

squid: information disclosure due to incorrect handling of peer responses in tunnel.cc (SQUID-2015:2)

  • Red Hat Enterprise Linux 5 squid Red Hat Enterprise Linux 6 squid Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script
    affected: no fix planned “Will not fix”

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

Exploit prediction

20.84% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • squid-cache.org http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-13856.patch referenced PoC, tagged "exploit" by a source, unverified
  • openwall.com http://www.openwall.com/lists/oss-security/2015/07/17/14 referenced PoC, tagged "exploit" by a source, unverified
  • squid-cache.org http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10494.patch referenced PoC, tagged "exploit" by a source, unverified
  • squid-cache.org http://www.squid-cache.org/Versions/v3/3.4/changesets/squid-3.4-13225.patch referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Intel 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.