GHSA-h383-gmxw-35v2
GHSA-h383-gmxw-35v2 is a CWE-116 vulnerability in org.apache.logging.log4j:log4j-1.2-api. O3 Security confirms whether GHSA-h383-gmxw-35v2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Apache Log4j 1 to Log4j 2 bridge: silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters
Blast Radius
org.apache.logging.log4j:log4j-1.2-api☕org.apache.logging.log4j:log4j-1.2-apiReal-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
The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.
Two groups of users are affected:
- Those using
Log4j1XmlLayoutdirectly in a Log4j Core 2 configuration file. - Those using the Log4j 1 configuration compatibility layer with
org.apache.log4j.xml.XMLLayoutspecified as the layout class.
Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.
[!NOTE] The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide, and specifically the section on eliminating reliance on the bridge.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.logging.log4j:log4j-1.2-api | ≥ 2.7&&< 2.25.4 | 2.25.4 |
| ☕Maven | org.apache.logging.log4j:log4j-1.2-api | ≥ 3.0.0-beta1 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.logging.log4j:log4j-1.2-api. 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.
Fix
Update org.apache.logging.log4j:log4j-1.2-api to 2.25.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h383-gmxw-35v2 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 pinpoints whether GHSA-h383-gmxw-35v2 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-h383-gmxw-35v2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-h383-gmxw-35v2 in your dependencies?
O3 detects GHSA-h383-gmxw-35v2 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.