CVE-2009-0804: Ziproxy 2.6.0, when transparent interception mode is enabled, uses the HTTP Host header to determine the remot

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MEDIUM 5.4DOWNGRADE

CVE-2009-0804 is a medium-severity flaw (CVSS 5.4) affecting ziproxy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Ziproxy 2.6.0, 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.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.4 (Medium)
EPSS exploit chance	2.4% (top 16%)
CISA exploited list	No
Weakness	CWE-264
Published	2009-03-04
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ziproxy

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-03-04 16:30 UTCPublished CVE record published
2026-06-16 23:05 UTCUpdated Record last modified

ziproxy ziproxy DOWNGRADE

Affected: 2.6.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.6.0

1. Check installed version

apt-cache policy ziproxy || rpm -q ziproxy || ziproxy --version

2. No fixed release: DOWNGRADE to a release before 2.6.0 (Debian / Ubuntu)

apt-cache madison ziproxy sudo apt install ziproxy=<VERSION_BEFORE_2.6.0> sudo apt-mark hold ziproxy

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ziproxy sudo dnf downgrade ziproxy-<VERSION_BEFORE_2.6.0> sudo dnf versionlock add ziproxy

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2009-0804?

ziproxy: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-0804 being exploited?

CVE-2009-0804 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2009-0804 affect?

CVE-2009-0804 affects ziproxy. Severity is medium (CVSS 5.4). Ziproxy 2.6.0, 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,

How urgent is CVE-2009-0804?

Priority 40/100. No elevated risk signals yet.

Software pages

Java vulnerabilities

Related CVEs

CVE-2010-2350 MEDIUM 6.8 DOWNGRADE Heap-based buffer overflow in the PNG decoder in Ziproxy 3.1.0 allows remote attackers to cause a denial of se
CVE-2010-1513 MEDIUM 6.8 UPGRADE Multiple integer overflows in src/image.c in Ziproxy before 3.0.1 allow remote attackers to execute arbitrary

References

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