Code execution via unverified Stanford Segmenter JARs
Published Mar 5, 2026 · Updated Mar 5, 2026
Code execution in NLTK 3.9.2 and earlier allows attackers to run arbitrary Java bytecode through an untrusted Stanford Segmenter JAR. StanfordSegmenter builds a Java classpath from the supplied JAR and invokes the JVM through subprocess without verifying the JAR's origin or integrity. Exploitation requires control of the configured JAR through direct supply, replacement, model poisoning, or a dependency or network-path compromise, after which the bytecode runs with the application's privileges.
Summary
What happened
Code execution in NLTK 3.9.2 and earlier allows attackers to run arbitrary Java bytecode through an untrusted Stanford Segmenter JAR. StanfordSegmenter builds a Java classpath from the supplied JAR and invokes the JVM through subprocess without verifying the JAR's origin or integrity. Exploitation requires control of the configured JAR through direct supply, replacement, model poisoning, or a dependency or network-path compromise, after which the bytecode runs with the application's privileges.
The record
- CVE
- CVE-2026-0848
- Published
- Mar 5, 2026
- Updated
- Mar 5, 2026
- Vendor
- NLTK Project
- Product
- NLTK
- Classifications
- CWE-20, T1195.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 5, 2026CVE publishedPublication date reported by the CVE source.
- Mar 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <=latest
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Huntr CVE-2026-0848 proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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