CVE-2026-67211 Apache OpenNLP - Denial of Service

Apache OpenNLP 3.0.0-M4 and 3.0.0-M5 contain a denial of service caused by unbounded map pre-sizing in SymSpellModelSerializer.create() when reading attacker-controlled count fields from a binary model, letting attackers exhaust heap memory, exploit requires loading untrusted SymSpell model files.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.74% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
11 September 2026
Updated
15 October 2026
Weakness
CWE-789

Vendor fix

Upgrade to version 3.0.0-M6 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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