# CVE-2026-123356: GROBID: Unauthenticated `/api/modelTraining` Endpoint Allows Unbounded Thread Pool Creation (DoS)

Status: published. Published: 2026-11-06. Updated: 2026-11-09.

GROBID is machine learning software for extracting information from scholarly documents. Prior to 0.9.1, the unauthenticated /api/modelTraining endpoint calls GrobidRestProcessTraining.trainModel in GrobidRestProcessTraining.java, where each request creates Executors.newFixedThreadPool(1), submits a training task, and leaves the executor running. Repeated requests permanently retain JVM worker threads and can exhaust process or operating-system thread capacity, degrading or stopping request processing. This issue is fixed in version 0.9.1.

## Remediation

- fix: kermitt2/grobid (other): GitHub reports patched versions 0.9.1. Check the advisory for the affected release branch. (source: GitHub GHSA-g2r5-4c8r-c84f) — https://github.com/grobidOrg/grobid/security/advisories/GHSA-g2r5-4c8r-c84f

## Affected products and versions

- grobidOrg / grobid: < 0.9.1 (affected). Source: CNA: GitHub_M
-  / kermitt2/grobid (kermitt2/grobid): 0.9.0 (affected, GitHub advisory range). Source: GitHub GHSA-g2r5-4c8r-c84f

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.35% as of 2026-11-09; percentile 28.90%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-400

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/grobidOrg/grobid/security/advisories/GHSA-g2r5-4c8r-c84f (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/grobidOrg/grobid/pull/1477 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/grobidOrg/grobid/commit/3227e9a6a990ec1687173045f119c24e17d10103 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/grobidOrg/grobid/releases/tag/0.9.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/grobidOrg/grobid/commit/3227e9a6a990ec1687173045f119c24e17d10103 (security-advisories@github.com)

- https://github.com/grobidOrg/grobid/pull/1477 (security-advisories@github.com)

- https://github.com/grobidOrg/grobid/releases/tag/0.9.1 (security-advisories@github.com)

- https://github.com/grobidOrg/grobid/security/advisories/GHSA-g2r5-4c8r-c84f (security-advisories@github.com)

- https://github.com/grobidOrg/grobid/security/advisories/GHSA-g2r5-4c8r-c84f (GitHub Security Advisories; advisory)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-123356; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123356; retrieved 2026-11-10; source updated 2026-11-09

- GitHub Security Advisories: https://github.com/grobidOrg/grobid/security/advisories/GHSA-g2r5-4c8r-c84f; retrieved 2026-11-08; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123356; retrieved 2026-11-09; source updated Not reported

Revision: f6a83d385f4cdb72235c433f660f811649f96185b222aff87fab4ac1e85fcebf

Canonical: https://y2.dev/cve/CVE-2026-123356

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