CVE-2008-6547: schema.py in FormEncode for Python (python-formencode) 1.0 does not apply the chained_validators feature, whic

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HIGH 7.5DOWNGRADE

CVE-2008-6547 is a high-severity flaw (CVSS 7.5) affecting formencode. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

schema.py in FormEncode for Python (python-formencode) 1.0 does not apply the chained_validators feature, which allows attackers to bypass intended access restrictions via unknown vectors.

Why this priority

High severity

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-20
Published	2009-03-30
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: formencode

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

Am I affected?

Timeline

2009-03-30 01:30 UTCPublished CVE record published
2026-06-16 23:02 UTCUpdated Record last modified

formencode formencode DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison formencode sudo apt install formencode=<VERSION_BEFORE_1.0> sudo apt-mark hold formencode

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

dnf --showduplicates list formencode sudo dnf downgrade formencode-<VERSION_BEFORE_1.0> sudo dnf versionlock add formencode

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-2008-6547?

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

Is CVE-2008-6547 being exploited?

CVE-2008-6547 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-2008-6547 affect?

CVE-2008-6547 affects formencode. Severity is high (CVSS 7.5). schema.py in FormEncode for Python (python-formencode) 1.0 does not apply the chained_validators feature, which allows attackers to bypass intended access restrictions via unknown vectors.

How urgent is CVE-2008-6547?

Priority 45/100. High severity

Software pages

Python vulnerabilities

References

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