CVE-2025-3262
Regular Expression Denial of Service (ReDoS) in huggingface/transformers
CVE-2025-3262 is a medium vulnerability (CVSS 5.3) in Huggingface Huggingface/transformers, published July 7, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.49%, the 42nd percentile. Fixed in transformers 4.51.0.
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
5.3
Regular Expression Denial of Service (ReDoS) in huggingface/transformers
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
CVE-2025-3262- CVSS 3.0
- 5.3 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1333
- Updated
- 2026-11-02
EUVDEUVD-2025-20217
5.3
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
EUVD-2025-20217- CVSS 3.0
- 5.3 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-489j-g2vx-39wf
5.3
Transformers vulnerable to ReDoS attack through its SETTING_RE variable
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
GHSA-489j-g2vx-39wf- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1333
- Updated
- 2026-11-02
NVD
7.5
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
CVE-2025-3262- 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 - CVSS 3.0
- 5.3 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSV
5.3
Regular Expression Denial of Service (ReDoS) in huggingface/transformers
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
CVE-2025-3262- CVSS 3.0
- 5.3 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSVGHSA-489j-g2vx-39wf
5.3
Transformers vulnerable to ReDoS attack through its SETTING_RE variable
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
GHSA-489j-g2vx-39wf- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSVPYSEC-2026-1979
5.3
Transformers vulnerable to ReDoS attack through its SETTING_RE variable
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the SETTING_RE variable within the transformers/commands/chat.py file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
- Record
PYSEC-2026-1979- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
transformersPyPI |
4.49.0 up to 4.51.0 | 4.51.0 |
transformersPyPI |
4.49.0 up to 4.51.0, plus listed versions 4.50.04.50.14.50.24.50.3 |
4.51.0 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
huntr.com/bounties/ecf5ccc4-39e7-4fb3-b547-14a41d31a184
github.com/huggingface/transformers/commit/0720e206c6ba28887e4d60ef60a6a089f6c1cc76
nvd.nist.gov/vuln/detail/CVE-2025-3262
github.com/huggingface/transformers/commit/126abe3461762e5fc180e7e614391d1b4ab051ca
github.com/advisories/GHSA-489j-g2vx-39wf
github.com/CVEProject/cvelistV5/tree/main/cves/2025/3xxx/CVE-2025-3262.json
github.com/huggingface/transformers
pypi.org/project/transformers