CVE-2026-43825: Untrusted Java Deserialization in Apache OpenNLP SvmDoccatModel Versions Affected: before 3.0.0-M4 (libsvm

This week

HIGH 7.3REMOTEWATCHLISTDOWNGRADE

CVE-2026-43825 is a high-severity flaw (CVSS 7.3) affecting opennlp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
EPSS top 3%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	13.9% (top 3%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-07-06
Last modified	2026-10-25

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-06 17:16 UTCPublished CVE record published
2026-10-25 20:10 UTCUpdated Record last modified

apache opennlp DOWNGRADE

Affected: 3.0.0 m1 · 3.0.0 m2 · 3.0.0 m3

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.0

1. Check installed version

apt-cache policy opennlp || rpm -q opennlp || opennlp --version

2. No fixed release: DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison opennlp sudo apt install opennlp=<VERSION_BEFORE_3.0.0> sudo apt-mark hold opennlp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list opennlp sudo dnf downgrade opennlp-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add opennlp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · python-apprise · FIXED · 2.1.0-1.fc46 · FEDORA-2026-ef67a72c5d · source

sudo dnf upgrade --advisory=FEDORA-2026-ef67a72c5d

Debian 12 · apache-opennlp · NOT AFFECTED

Debian 13 · apache-opennlp · NOT AFFECTED

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43825?

opennlp: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-43825 being exploited?

CVE-2026-43825 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43825 affect?

CVE-2026-43825 affects opennlp. Severity is high (CVSS 7.3). 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.deseri

How urgent is CVE-2026-43825?

Priority 60/100. High severity; EPSS top 3%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Java vulnerabilities

Related CVEs

CVE-2026-63317 MEDIUM 5.6 UPGRADE Arbitrary Class Instantiation via XML Feature Generator Descriptor and Format Name in Apache OpenNLP Versions

References

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