Medium severity · published Mar 26, 2026
CVE-2026-33515
Squid has issues in ICP message handling
6.5
CVSS
1.1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 64% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SQ
squid · squid-cache
< 7.5 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33515
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33515
Patch
https://github.com/squid-cache/squid/commit/8138e909d2058d4401e0ad49b583afaec912b165
Issue Tracking
https://github.com/squid-cache/squid/pull/2220
Issue Tracking
https://github.com/squid-cache/squid/pull/2220#discussion_r2727683637
Vendor Advisory
https://github.com/squid-cache/squid/security/advisories/GHSA-84p4-hcx7-jj7c
Mailing List
http://www.openwall.com/lists/oss-security/2026/03/25/4
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