Regular Expression Denial of Service (ReDoS) in huggingface/transformers
The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.
- Published
- Sep 23, 2025
- Updated
- Jun 17, 2026
- EPSS
- 0.5% · 41th percentile
- CWE
- CWE-400
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · @huntr_ai
- 5.3
- 2.2 point gap
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| huggingface | transformers | cpe:2.3:a:huggingface:transformers |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- huggingface transformersbefore 4.53.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (@huntr_ai). Independent of NVD's CPE analysis and usually ahead of it.
huggingface huggingface/transformers
- unspecified and later · before 4.53.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| openSUSE:Tumbleweed | python-transformers | before 5.15.0-1.1 | 5.15.0-1.1 |
| PyPI | transformers | before 4.53.0 | 4.53.0 |
Same product
huggingface: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-3568Arbitrary Code Execution via Deserialization in huggingface/transformers39Monitor
- CVE-2026-5241Policy Bypass in LightGlue Nested Config Resolution in huggingface/transformers38Monitor
- CVE-2024-11392Hugging Face Transformers MobileViTV2 Deserialization of Untrusted Data Remote Code Execution Vulnerability37Monitor
- CVE-2024-11394Hugging Face Transformers Trax Model Deserialization of Untrusted Data Remote Code Execution Vulnerability36Monitor
- CVE-2024-11393Hugging Face Transformers MaskFormer Model Deserialization of Untrusted Data Remote Code Execution Vulnerability36Monitor
- CVE-2023-6730Deserialization of Untrusted Data in huggingface/transformers35Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| opensuse:python-transformers | 5.15.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| PyPI:transformers | 4.53.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-400 · Uncontrolled Resource ConsumptionCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Root cause
Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.
The bug in code
The whole CWE-400 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
function expand(node) { return node.children.map(expand);}Fixed
const MAX_DEPTH = 32;function expand(node, depth = 0) { if (depth > MAX_DEPTH) throw new Error("too deep"); return node.children.map((c) => expand(c, depth + 1));}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.