Skip to content
Fencer Vulns
medium 5.3

CVE-2025-2099 json

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

published 2025-05-19 17 mo ago modified 2026-06-17 4 mo ago also GHSA-qq3j-4f4f-9583 , PYSEC-2025-40 , EUVD-2025-15691

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi transformers 4.49.0, 4.50.0
  • huggingface huggingface/transformers 4.50.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-2099 updated cvss 7.5

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

  • Red Hat Enterprise Linux AI (RHEL AI) rhelai1/ui-rhel9, rhelai1/bootc-intel-rhel9, rhelai1/docling-serve-rhel9, rhelai1/instructlab-intel-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Ansible Automation Platform 2.5 for RHEL 8 ansible-automation-platform-25/lightspeed-chatbot-rhel8 2.5.250730-2
    fixed: vendor fix RHSA-2025:12791
  • Red Hat OpenShift Lightspeed openshift-lightspeed-tech-preview/lightspeed-service-api-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-24/de-minimal-rhel8, ansible-automation-platform-24/de-minimal-rhel9, ansible-automation-platform-25/de-minimal-rhel8, ansible-automation-platform-25/de-minimal-rhel9 Red Hat Ansible Automation Platform 2.5 for RHEL 8 ansible-automation-platform-25/hub-rhel8 4.10.6-3, ansible-automation-platform-25/hub-web-rhel8 4.10.6-3, ansible-automation-platform-25/receptor-rhel8 1.5.7-4, ansible-automation-platform-25/de-minimal-rhel8 1.1.7-6, ansible-automation-platform-25/controller-rhel8 4.6.18-1, ansible-automation-platform-25/de-supported-rhel8 1.1.7-5, +26 more Red Hat Ansible Automation Platform 2.5 for RHEL 9 ansible-automation-platform-25/de-minimal-rhel9 1.1.7-7, ansible-automation-platform-25/de-supported-rhel9 1.1.7-6, ansible-automation-platform-25/ee-minimal-rhel9 1.0.0-945, ansible-automation-platform-25/ee-supported-rhel9 1.0.0-1063, ansible-automation-platform-25/ansible-builder-rhel9 3.1.0-249, ansible-automation-platform-25/ee-cloud-services-rhel9 1.0.0-312, +2 more Red Hat Enterprise Linux AI (RHEL AI) rhelai1/bootc-amd-rhel9, rhelai1/bootc-nvidia-rhel9, rhelai1/bootc-azure-amd-rhel9, rhelai1/instructlab-amd-rhel9, rhelai1/bootc-aws-nvidia-rhel9, rhelai1/bootc-gcp-nvidia-rhel9, +2 more Red Hat OpenShift AI (RHOAI) rhoai/odh-training-operator-rhel8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.com https://huntr.com/bounties/97b780f3-ffca-424f-ad5d-0e1c57a5bde4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi transformers
<4.50.0
<4.49.0
4.50.0
4.49.0

Affected products

  • huggingface huggingface/transformers

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.