CVE-2026-40682: XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor Vers

Q: How do I fix CVE-2026-40682?

opennlp: upgrade to 2.5.9. Exact commands for each OS are on this page.

Q: Is CVE-2026-40682 being exploited?

CVE-2026-40682 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-40682 affect?

CVE-2026-40682 affects opennlp. Severity is critical (CVSS 9.1). XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor Versions Affected: before 2.5.9, before 3.0.0-M3 Description: The DictionaryEntryPersistor class initializes a static SAXParserFacto

Q: How urgent is CVE-2026-40682?

Priority 52/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

This month

CRITICAL 9.1REMOTEWATCHLISTUPGRADE

CVE-2026-40682 is a critical-severity flaw (CVSS 9.1) affecting opennlp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor Versions Affected: before 2.5.9, before 3.0.0-M3 Description: The DictionaryEntryPersistor class initializes a static SAXParserFactory at class-load time without enabling FEATURE_SECURE_PROCESSING or disabling DTD processing. When create(InputStream, EntryInserter) is invoked, the only feature set on the XMLReader is namespace support — ext

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-611
Published	2026-05-04
Last modified	2026-10-26

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

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-04 17:16 UTCPublished CVE record published
2026-10-26 19:10 UTCUpdated Record last modified

apache opennlp UPGRADE

Affected: < 2.5.9 · 3.0.0 m1 · 3.0.0 m2

Fixed in: 2.5.9

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 2.5.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade opennlp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade opennlp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2026-40682?

opennlp: upgrade to 2.5.9. Exact commands for each OS are on this page.

Is CVE-2026-40682 being exploited?

CVE-2026-40682 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-2026-40682 affect?

CVE-2026-40682 affects opennlp. Severity is critical (CVSS 9.1). XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor Versions Affected: before 2.5.9, before 3.0.0-M3 Description: The DictionaryEntryPersistor class initializes a static SAXParserFacto

How urgent is CVE-2026-40682?

Priority 52/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-42027 CRITICAL 9.8 UPGRADE Arbitrary Class Instantiation via Model Manifest in Apache OpenNLP ExtensionLoader Versions Affected: bef
CVE-2026-42440 HIGH 7.5 UPGRADE OOM Denial of Service via Unbounded Array Allocation in Apache OpenNLP AbstractModelReader Versions Affected
CVE-2026-43825 HIGH 7.3 DOWNGRADE Untrusted Java Deserialization in Apache OpenNLP SvmDoccatModel Versions Affected: before 3.0.0-M4 (libsvm
CVE-2026-63317 MEDIUM 5.6 UPGRADE Arbitrary Class Instantiation via XML Feature Generator Descriptor and Format Name in Apache OpenNLP Versions
CVE-2026-82617 CRITICAL 9.8 UPGRADE The two built-in name-finder patterns exposed by opennlp.tools.namefind.RegexNameFinderFactory - DEFAULT_REGEX

References

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