CVE-2026-0848 | Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading

Exp

NLTK versions <=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM.

Published: 2026-03-05 Last update: 2026-04-21 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-0848 is rated High Exploit Risk (73.5/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.29%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-0848

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-0848

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-22 0.18% 0.29% +0.11%
2 2026-04-21 0.48% 0.18% -0.30%
3 2026-03-11 — 0.48% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-0848

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]

Weakness enumeration for CVE-2026-0848

OS Trackers for CVE-2026-0848

vendor priority summary link
debian not yet assigned CVE-2026-0848 not yet assigned priority: Debian including 1 source packages (nltk), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-0848
redhat — — https://access.redhat.com/security/cve/CVE-2026-0848
suse critical — https://www.suse.com/security/cve/CVE-2026-0848/
ubuntu medium CVE-2026-0848 medium priority: Ubuntu including 1 source packages (nltk), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needed 7, released 1. https://ubuntu.com/security/CVE-2026-0848

Affected software / configurations for CVE-2026-0848

Vendor Product Version Raw CPE
nltk nltk <= 3.9.2 cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

References for CVE-2026-0848

cvelogic Threat Intelligence