How severe is GHSA-523c-xh4g-mh5m?

GHSA-523c-xh4g-mh5m has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-523c-xh4g-mh5m?

GHSA-523c-xh4g-mh5m affects the following packages: org.apache.poi:poi (Maven). Ecosystems affected: Maven.

How do I fix GHSA-523c-xh4g-mh5m?

Update org.apache.poi:poi to 3.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-523c-xh4g-mh5m is resolved across your whole dependency graph.

How do I detect GHSA-523c-xh4g-mh5m in my Maven dependencies?

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

How do I mitigate GHSA-523c-xh4g-mh5m if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-523c-xh4g-mh5m actively exploited in the wild?

No public exploit code has been indexed for GHSA-523c-xh4g-mh5m 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 GHSA-523c-xh4g-mh5m?

GHSA-523c-xh4g-mh5m has an EPSS (Exploit Prediction Scoring System) score of 10.1%, placing it in the 96th 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 warrants monitoring and prompt remediation.

What type of vulnerability is GHSA-523c-xh4g-mh5m?

GHSA-523c-xh4g-mh5m is classified as CWE-835 (CWE-835). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-523c-xh4g-mh5m published, and has it been updated?

GHSA-523c-xh4g-mh5m was published on January 14, 2021 and was last updated on June 9, 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

HIGH severity

Denial of Service in Apache POIGHSA-523c-xh4g-mh5m

HIGH

GHSA-523c-xh4g-mh5m is a high-severity (CVSS 7.5) CWE-835 vulnerability in org.apache.poi:poi. EPSS puts its 30-day exploitation probability at 10.1% (96th percentile). A fix is available for org.apache.poi:poi — see the affected versions and patch details below.

Also known asCVE-2017-12626

Published

Jan 14, 2021

Updated

Jun 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-523c-xh4g-mh5m.

EPSS Exploitation Probability

via FIRST.org ↗

10.1%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.apache.poi:poi

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

Apache POI in versions prior to release 3.17 are vulnerable to Denial of Service Attacks: 1) Infinite Loops while parsing crafted WMF, EMF, MSG and macros (POI bugs 61338 and 61294), and 2) Out of Memory Exceptions while parsing crafted DOC, PPT and XLS (POI bugs 52372 and 61295).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.poi:poi`	all versions	3.17`org.apache.poi:poi:3.17`

Affected Products

1 product · 1 configurations

Application

poiapache

< 3.17

range

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.poi:poi, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.poi:poi to 3.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-523c-xh4g-mh5m is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

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 HatModerate

Product	Fixed in	Advisory
Red Hat JBoss A-MQ 6.3	`poi`	RHSA-2018:1322

Frequently Asked Questions

Apache POI in versions prior to release 3.17 are vulnerable to Denial of Service Attacks: - Infinite Loops while parsing crafted WMF, EMF, MSG and macros (POI bugs 61338 and 61294) - Out of Memory Exceptions while parsing crafted DOC, PPT and XLS (POI bugs 52372 and 61295)

O3 Security · Impact-Aware SCA

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