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Maven

GHSA-p6xc-xr62-6r2g

HIGH

Apache Log4j2 vulnerable to Improper Input Validation and Uncontrolled Recursion

Also known asCVE-2021-45105
Published
Dec 18, 2021
Updated
Jun 9, 2026
Affected
7 pkgs
Patched
7 / 7
Exploits
4 known

EPSS Exploitation Probability

via FIRST.org ↗
100.0%probability of exploitation in next 30 days
Very High Risk100th percentile0.00%
55.3%70.2%85.1%100.0%65.6%100.0%Jan 26May 26Jul 26

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.

Blast Radius

7 pkgs affected
org.apache.logging.log4j:log4j-coreorg.apache.logging.log4j:log4j-coreorg.apache.logging.log4j:log4j-coreorg.ops4j.pax.logging:pax-logging-log4j2org.ops4j.pax.logging:pax-logging-log4j2org.ops4j.pax.logging:pax-logging-log4j2org.ops4j.pax.logging:pax-logging-log4j2

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 Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0 and 2.12.3.

Affected packages

Only the org.apache.logging.log4j:log4j-core package is directly affected by this vulnerability. The org.apache.logging.log4j:log4j-api should be kept at the same version as the org.apache.logging.log4j:log4j-core package to ensure compatability if in use.

Affected Packages

7 total 7 fixed
EcosystemPackageVulnerable rangeFix
Mavenorg.apache.logging.log4j:log4j-core2.4.0&&< 2.12.32.12.3
Mavenorg.apache.logging.log4j:log4j-core2.13.0&&< 2.17.02.17.0
Mavenorg.apache.logging.log4j:log4j-coreall versions2.3.1
Mavenorg.ops4j.pax.logging:pax-logging-log4j21.8.0&&< 1.9.21.9.2
Mavenorg.ops4j.pax.logging:pax-logging-log4j21.10.0&&< 1.10.91.10.9
Mavenorg.ops4j.pax.logging:pax-logging-log4j21.11.0&&< 1.11.121.11.12
Exploits & PoCs
4

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.logging.log4j:log4j-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update org.apache.logging.log4j:log4j-core to 2.12.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p6xc-xr62-6r2g 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-p6xc-xr62-6r2g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-p6xc-xr62-6r2g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0 and 2.12.3. # Affected packages Only the `org.apache.logging.log4j:log4j-core` package is directly affected by this vulnerability. The `org.apache.logging.log4j:log4j-api` should be kept at the same version as the `org.apache.logging.log4j:log4j-core` package to ensure compatability i
O3 Security · Impact-Aware SCA

Is GHSA-p6xc-xr62-6r2g in your dependencies?

O3 detects GHSA-p6xc-xr62-6r2g across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.