How severe is CVE-2021-31812?

CVE-2021-31812 has a CVSS score of 5.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-31812?

CVE-2021-31812 affects the following packages: org.apache.pdfbox:pdfbox (Maven), org.apache.pdfbox:pdfbox-parent (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-31812?

Update org.apache.pdfbox:pdfbox to 2.0.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31812 is resolved across your whole dependency graph.

How do I detect CVE-2021-31812 in my Maven dependencies?

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

How do I mitigate CVE-2021-31812 if there is no patch (or I can't update yet)?

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.

How does O3 Security protect against CVE-2021-31812?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-31812 can be triaged on real exposure rather than presence alone.

Is CVE-2021-31812 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-31812 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-31812?

CVE-2021-31812 has an EPSS (Exploit Prediction Scoring System) score of 3.1%, placing it in the 87th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-31812?

CVE-2021-31812 is classified as CWE-834 (CWE-834), CWE-835 (CWE-835). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-31812 published, and has it been updated?

CVE-2021-31812 was published on June 12, 2021 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2021-31812 — pdfbox

MEDIUM

CVE-2021-31812 is a medium-severity (CVSS 5.5) CWE-834 vulnerability in org.apache.pdfbox:pdfbox. A fix is available for org.apache.pdfbox:pdfbox — see the affected versions and patch details below.

Infinite Loop in Apache PDFBox

Also known asGHSA-7grw-6pjh-jpc9

Published

Jun 12, 2021

Updated

Jul 8, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs87th percentile — riskier than 87% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2021-31812 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

2 pkgs affected

☕org.apache.pdfbox:pdfbox☕org.apache.pdfbox:pdfbox-parent

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

Description

In Apache PDFBox, a carefully crafted PDF file can trigger an infinite loop while loading the file. This issue affects Apache PDFBox version 2.0.23 and prior 2.0.x versions.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.pdfbox:pdfbox`	≥ 2.0.0&&< 2.0.24	2.0.24`org.apache.pdfbox:pdfbox:2.0.24`
☕Maven	`org.apache.pdfbox:pdfbox-parent`	≥ 2.0.0&&< 2.0.24	2.0.24`org.apache.pdfbox:pdfbox-parent:2.0.24`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.pdfbox:pdfbox, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.pdfbox:pdfbox to 2.0.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31812 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-31812 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2021-31812. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

RHSA-2021:4918Red Hat Integration

Frequently Asked Questions

In Apache PDFBox, a carefully crafted PDF file can trigger an infinite loop while loading the file. This issue affects Apache PDFBox version 2.0.23 and prior 2.0.x versions.

O3 Security · Impact-Aware SCA

Is CVE-2021-31812 in your dependencies?

O3 Security finds CVE-2021-31812 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works