CVE-2025-3264Network attack vector

CPU exhaustion via catastrophic regex backtracking

Published Jul 7, 2025 · Updated Jul 7, 2025

ReDoS in Hugging Face Transformers before 4.51.0 allows remote attackers to exhaust CPU through crafted Python source files. The get_imports function applies an unbounded try/except-block regular expression across file contents, causing catastrophic backtracking on malicious text. Exploitation requires attacker-controlled source to reach dynamic-module import discovery and can stall model-serving or development workloads.

CVSS severity5.3
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

ReDoS in Hugging Face Transformers before 4.51.0 allows remote attackers to exhaust CPU through crafted Python source files. The get_imports function applies an unbounded try/except-block regular expression across file contents, causing catastrophic backtracking on malicious text. Exploitation requires attacker-controlled source to reach dynamic-module import discovery and can stall model-serving or development workloads.

The record

CVE
CVE-2025-3264
Published
Jul 7, 2025
Updated
Jul 7, 2025
Vendor
Hugging Face
Product
Hugging Face Transformers
Classifications
CWE-1333, CAPEC-492, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 7, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 7, 2025Record 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.

  1. Affected versionversion=unspecified <4.51.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Hugging Face · Hugging Face Transformersversion=unspecified <4.51.0

Published CVSS scores

5.3National Vulnerability DatabaseCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
CAPEC-492Regular Expression Exponential Blowup
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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