CVE-2020-15810

high
Published — · Modified —
CVSS v3
CVSS v2
VIR risk
8.0

Description

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-15810

vendor Authored 2026-05-27

Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2020:3623

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-15810.html

OS impact

OSVersionStatusFixed in
suse slesaffected
rockylinux rocky8fixed
debian debianbookwormfixed4.13-1
debian debianbullseyefixed4.13-1
debian debianforkyfixed4.13-1
debian debiansidfixed4.13-1
debian debiantrixiefixed4.13-1

References

Verify integrity in audit chain (admin only). AS-IS.