High [CVE-2026-43825] Untrusted Java Deserialization in Apache OpenNLP SvmDoccatModel Versions Affected: before 3.0.0-M4 (libsvm document…
This high-severity Apache Software Foundation advisory covers CVE-2026-43825 affecting Apache OpenNLP SvmDoccatModel.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
Untrusted Java Deserialization in Apache OpenNLP SvmDoccatModel Versions Affected: before 3.0.0-M4 (libsvm document categorization module; introduced in OPENNLP-1808 and only present on the 3.x line) Description: SvmDoccatModel.deserialize(InputStream) reads an attacker-controlled stream with java.io.ObjectInputStream and calls readObject() without an ObjectInputFilter installed.
ObjectInputStream materialises every class referenced in the stream before the resulting object is cast to SvmDoccatModel, so the cast that follows readObject() executes only after the foreign object graph has already been deserialised in full.
If a Java deserialization gadget chain is available on the consumer's classpath, a crafted payload supplied to deserialize() executes arbitrary code in the JVM that loads it. Apache OpenNLP itself does not ship a known gadget chain, so the realistic risk is to downstream applications that embed the libsvm module alongside vulnerable transitive dependencies.
The method is public and static, so any caller can pass an untrusted stream to it directly. The practical impact is remote code execution against processes that load SvmDoccatModel instances from untrusted or semi-trusted origins.
Mitigation: 3.x users should upgrade to 3.0.0-M4.
Is CVE-2026-43825 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-43825 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-43825?
Upgrade to a fixed release named by Apache:
- 3.0.0-M4
Confirm against the vendor advisory before you patch.
- 3.0.0
Official advisory · high-confidence parse· fetched 4 months ago·verify at source
- 3.0.0-M4
Official advisory · high-confidence parse· fetched 4 months ago·verify at source
Mitigation checklist
- Mitigation: 3.x users should upgrade to 3.0.0-M4.
- Users who cannot upgrade immediately should treat all serialized SvmDoccatModel streams as untrusted input unless their provenance is verified, and should avoid invoking SvmDoccatModel.deserialize() on streams supplied by end users or fetched from third-party sources without integrity checks.
Official advisory · high-confidence parse· fetched 4 months ago·verify at source
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