CVE-2005-1857: Format string vulnerability in simpleproxy before 3.4 allows remote malicious HTTP proxies to execute arbitrar

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HIGH 7.5WATCHLISTDOWNGRADE

CVE-2005-1857 is a high-severity flaw (CVSS 7.5) affecting simpleproxy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in simpleproxy before 3.4 allows remote malicious HTTP proxies to execute arbitrary code via format string specifiers in a reply.

Why this priority

High severity
EPSS top 9%: very likely to be exploited
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	4.3% (top 9%)
CISA exploited list	No
Published	2005-09-02
Last modified	2026-06-16

Publisher (CNA): Debian GNU/Linux · Vendor: simpleproxy

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

Am I affected?

Timeline

2005-09-02 22:03 UTCPublished CVE record published
2026-06-16 22:13 UTCUpdated Record last modified

simpleproxy simpleproxy DOWNGRADE

Affected: 2.2b · 3.0 · 3.1 · 3.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2b

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.2b (Debian / Ubuntu)

apt-cache madison simpleproxy sudo apt install simpleproxy=<VERSION_BEFORE_2.2b> sudo apt-mark hold simpleproxy

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

dnf --showduplicates list simpleproxy sudo dnf downgrade simpleproxy-<VERSION_BEFORE_2.2b> sudo dnf versionlock add simpleproxy

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-2005-1857?

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

Is CVE-2005-1857 being exploited?

CVE-2005-1857 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-2005-1857 affect?

CVE-2005-1857 affects simpleproxy. Severity is high (CVSS 7.5). Format string vulnerability in simpleproxy before 3.4 allows remote malicious HTTP proxies to execute arbitrary code via format string specifiers in a reply.

How urgent is CVE-2005-1857?

Priority 54/100. High severity; EPSS top 9%: very likely to be exploited; On your watchlist

References

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