Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Apache OpenNLP opennlp-tools (Maven) versions before 2.5.9, and versions from 3.0.0-M1 before 3.0.0-M3, are affected. A crafted binary model file can set a count field so that the library attempts an oversized array allocation, causing an out-of-memory error that crashes any JVM loading the file. Users should upgrade to 2.5.9 or 3.0.0-M3, and until then should avoid loading model files from untrusted sources.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub Advisory Database |
- CISA KEV Not listed.
- EPSS 0.0060, the 49th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 4 May 2026, 18:30 UTC Confirmed by GitHub Advisory Database
- 31 Oct 2026, 14:17 UTC First seen by agentprime
- 31 Oct 2026, 14:17 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-659w-93r5-9j6m
- OSV: GHSA-659w-93r5-9j6m
- nvd.nist.gov/vuln/detail/CVE-2026-42440
- github.com/apache/opennlp/pull/1198
- github.com/apache/opennlp/commit/96a073f693f3a0ded808a475f7d7773c072bb8a1
- github.com/apache/opennlp/commit/fc9824a97709470353add08e44cf15dc08677094
- access.redhat.com/security/cve/CVE-2026-42440
- bugzilla.redhat.com/show_bug.cgi?id=2466494
- github.com/apache/opennlp
- github.com/apache/opennlp/blob/9a0a05466b3e46567e7999272ff72ee37b42976b/SECURITY.md?plain=1#L118
- github.com/apache/opennlp/releases/tag/opennlp-1.9.5
- github.com/apache/opennlp/releases/tag/opennlp-2.5.9
- github.com/apache/opennlp/releases/tag/opennlp-3.0.0-M3
- lists.apache.org/thread/s8xlkx1gqbxfsq48py5h6jphjvgqp1jo