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Fencer Vulns
medium 5.4

CVE-2009-0801 json

Squid, when transparent interception mode is enabled, uses the HTTP Host header to determine the remote endpoint, which allows remote attac…

published 2009-03-04 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-0799

cvss
5.4
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.1%
EPSS 3.1% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

Squid, when transparent interception mode is enabled, uses the HTTP Host header to determine the remote endpoint, which allows remote attackers to bypass access controls for Flash, Java, Silverlight, and probably other technologies, and possibly communicate with restricted intranet sites, via a crafted web page that causes a client to send HTTP requests with a modified Host header.

Patch / fix

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

debian advisories DEBIAN-CVE-2009-0801

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-2009-0801 updated cvss 1.8

squid: remote bypass of access controls

  • Red Hat Enterprise Linux 4 squid Red Hat Enterprise Linux 5 squid Red Hat Enterprise Linux 6 squid
    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

3.09% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 5.4 AV:N/AC:H/Au:N/C:C/I:N/A:N

Classification

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

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.