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Full vulnerability report · 2025
CVE-2025-2099High confidence

Regular Expression Denial of Service (ReDoS) in huggingface/transformers

huggingface · huggingface/transformers

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-15691

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A vulnerability in the `preprocess_string()` function of the `transformers.testing_utils` module in huggingface/transformers version v4.48.3 allows for a Regular Expression Denial of Service (ReDoS) attack. The regular expression used to process code blocks in docstrings contains nested quantifiers, leading to exponential backtracking when processing input with a large number of newline characters. An attacker can exploit this by providing a specially crafted payload, causing high CPU usage and potential application downtime, effectively resulting in a Denial of Service (DoS) scenario.

What

A vulnerability in the `preprocess_string()` function of the `transformers.testing_utils` module in huggingface/transformers version v4.48.3 allows for a Regular Expression Denial of Service (ReDoS) attack. The regular expression used to process code blocks in docstrings contains nested quantifiers, leading to exponential backtracking when processing input with a large number of newline characters. An attacker can exploit this by providing a specially crafted payload, causing high CPU usage and potential application downtime, effectively resulting in a Denial of Service (DoS) scenario.

Why

The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A vulnerability in the `preprocess_string()` function of the `transformers.testing_utils` module in huggingface/transformers version v4.48.3 allows for a Regular Expression Denial of Service (ReDoS) attack. The regular expression used to process code blocks in docstrings contains nested quantifiers, leading to exponential backtracking when processing input with a large number of newline characters. An attacker can exploit this by providing a specially crafted payload, causing high CPU usage and potential application downtime, effectively resulting in a Denial of Service (DoS) scenario.

Why

The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Inefficient Regular Expression Complexity → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-1333

CWE-1333: Inefficient Regular Expression Complexity. The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-1333Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2025-1707Red Hat Ansible Automation Platform: Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Red Hat Ansible Automation Platform ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0556Multiples vulnérabilités dans les produits VMware

ord?id=CVE-2025-13837 Référence CVE CVE-2025-14009 https://www.cve.org/CVERecord?id=CVE-2025-14009 Référence CVE CVE-2025-14819 https://www.cve.org/CVERecord?id=CVE-2025-14819 Référence CVE CVE-2025-14831 https://www.cve.org/CVERecord?id=CVE-2025-14831 Référence CVE CVE-2025-15281 https://www.cve.org/CVERecord?id=CVE-2025-15281 Référence CVE CVE-2025-15282 https://www.cve.org/CVERecord?id=CVE-2025-15282 Référence CVE CVE-2025-15366 https://www.cve.org/CVERecord?id=CVE-2025-15366 Référence CVE CVE-2025-15367 https://www.cve.org/CVERecord?id=CVE-2025-15367 Référence CVE CVE-2025-1795 https://www.cve.org/CVERecord?id=CVE-2025-1795 Référence CVE CVE-2025-2099 https://www.cve.org/CVERecord?id=CVE-2025-2099 Référence CVE CVE-2025-21493 https://www.cve.org/CVERecord?id=CVE-2025-21493 Référence CVE CVE-2025-21499 https://www.cve.org/CVERecord?id=CVE-2025-21499 Référence CVE CVE-2025-21574 https://www.cve.org/CVERecord?id=CVE-2025-21574 Référence CVE CVE-2025-21575 https://www.cve.org/CVERecord?id=CVE-2025-21575 Référence CVE CVE-2025-21577 https://www.cve.org/CVERecord?id=CVE-2025-21577 Référence CVE CVE-2025-21579 https://www.cve.org/CVERecord?id=CVE-2025-21579 Référence CVE CVE-2025-21580 https://www.cve.org/CVERecord?id=CVE-2025-21580 Référence CVE CVE-2025-21581 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0969Multiples vulnérabilités dans les produits VMware

.cve.org/CVERecord?id=CVE-2025-1352 Référence CVE CVE-2025-1365 https://www.cve.org/CVERecord?id=CVE-2025-1365 Référence CVE CVE-2025-1371 https://www.cve.org/CVERecord?id=CVE-2025-1371 Référence CVE CVE-2025-1372 https://www.cve.org/CVERecord?id=CVE-2025-1372 Référence CVE CVE-2025-1376 https://www.cve.org/CVERecord?id=CVE-2025-1376 Référence CVE CVE-2025-1377 https://www.cve.org/CVERecord?id=CVE-2025-1377 Référence CVE CVE-2025-1390 https://www.cve.org/CVERecord?id=CVE-2025-1390 Référence CVE CVE-2025-1632 https://www.cve.org/CVERecord?id=CVE-2025-1632 Référence CVE CVE-2025-1795 https://www.cve.org/CVERecord?id=CVE-2025-1795 Référence CVE CVE-2025-2099 https://www.cve.org/CVERecord?id=CVE-2025-2099 Référence CVE CVE-2025-2148 https://www.cve.org/CVERecord?id=CVE-2025-2148 Référence CVE CVE-2025-2149 https://www.cve.org/CVERecord?id=CVE-2025-2149 Référence CVE CVE-2025-21502 https://www.cve.org/CVERecord?id=CVE-2025-21502 Référence CVE CVE-2025-21574 https://www.cve.org/CVERecord?id=CVE-2025-21574 Référence CVE CVE-2025-21575 https://www.cve.org/CVERecord?id=CVE-2025-21575 Référence CVE CVE-2025-21577 https://www.cve.org/CVERecord?id=CVE-2025-21577 Référence CVE CVE-2025-21579 https://www.cve.org/CVERecord?id=CVE-2025-21579 Référence CVE CVE-2025-21580 https://www.cve.org/CVERecord?id=CVE-2

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
unspecified < 4.50.0
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 19 May 2025 · Last source change 19 May 2025, 13:45 UTC · CWE-1333 · Inefficient Regular Expression Complexity

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-15691
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-2099 · cve.blacktree.nl