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Servers and applications

CVE-2020-24606

SQUID-2020:9 Denial of Service processing Cache Digest Response

Severity
High 7.5
Published
23 Aug 2020
Last changed
17 Jun 2026
Added to UpHeron
1 Nov 2026
Fixed in
4.13, 5.0.4
Also known as
GHSA-vvj7-xjgq-g2jg
Sources
NVD, Project advisories (GitHub)

Description

Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply() livelocking in peer_digest.cc mishandles EOF.

Affected software

SoftwareAffected versions
SquidServers and applications · cpe:a:squid-cache:squid
  • From 3.0 before 4.13
  • From 5.0.1 before 5.0.4
SquidServers and applications · github:squid-cache/squid
  • From 5.0.1 before 5.0.4

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2020-24606
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2020-24606
  • GitHub Advisory Database https://github.com/advisories/GHSA-vvj7-xjgq-g2jg
  • github.com https://github.com/squid-cache/squid/security/advisories/GHSA-vvj7-xjgq-g2jg