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Not in CISA KEV
HIGH severity

CVE-2021-29421 — pikepdf

HIGHFix: pikepdf/pikepdf@3f38f73

CVE-2021-29421 is a high-severity (CVSS 7.5) XML External Entity (XXE) vulnerability in pikepdf. A fix is available for pikepdf — see the affected versions and patch details below.

Improper Restriction of XML External Entity Reference in pikepdf

Also known asGHSA-ccgm-3xw4-h5p8PYSEC-2021-34
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs76th percentile — riskier than 76% of all scored CVEsHighest risk
0.00%0.74%1.48%2.21%0.4%1.7%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-29421 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍pikepdf

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

models/metadata.py in the pikepdf package 1.3.0 through 2.9.2 for Python allows XXE when parsing XMP metadata entries.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpikepdf≥ 1.3.0&&< 2.10.02.10.0pip install --upgrade 'pikepdf==2.10.0'

Affected Products

2 products · 3 configurations
OS
fedorafedoraproject
2 versions
3233
Application
pikepdfpikepdf_project
≥ 1.3.0 && ≤ 2.9.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pikepdf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update pikepdf to 2.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29421 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

models/metadata.py in the pikepdf package 1.3.0 through 2.9.2 for Python allows XXE when parsing XMP metadata entries.
O3 Security · Impact-Aware SCA

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CVE-2021-29421: pikepdf XXE — Fixed in 2.10.0