CVE-2025-66960
Published: 21 January 2026
Summary
CVE-2025-66960 is a high-severity Improper Input Validation (CWE-20) vulnerability in Ollama Ollama. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 29.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
This vulnerability is AI-related — categorised as NLP and Transformers; in the Data-Related Vulnerabilities risk domain.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2025-66960 is a denial-of-service vulnerability affecting Ollama version 0.12.10. The issue resides in the fs/ggml/gguf.go file, specifically the readGGUFV1String function, which reads a string length directly from untrusted GGUF metadata without proper validation. This flaw, associated with CWE-20 (Improper Input Validation) and CWE-400 (Uncontrolled Resource Consumption), carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and was published on 2026-01-21T18:16:23.950.
A remote attacker can exploit this vulnerability without authentication privileges or user interaction by supplying malicious GGUF metadata to an Ollama instance listening over the network. Successful exploitation triggers a panic or resource exhaustion in the readGGUFV1String function, resulting in high-impact denial of service that crashes the service or renders it unavailable.
Mitigation details are available in the referenced advisories, including the Ollama GitHub issue at https://github.com/ollama/ollama/issues/9820 and the technical analysis at https://zero.shotlearni.ng/blog/cve-2025-66960guf-v1-string-length-cause-panic-in-readggufv1string/.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3603
Vulnerability details
An issue in ollama v.0.12.10 allows a remote attacker to cause a denial of service via the fs/ggml/gguf.go, function readGGUFV1String reads a string length from untrusted GGUF metadata
- CWE(s)
AI Security AnalysisAI
- AI Category
- NLP and Transformers
- Risk Domain
- Data-Related Vulnerabilities
- OWASP Top 10 for LLMs 2025
- None mapped
- Classification Reason
- Matched keywords: ggml, ollama
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes remote exploitation of an input validation flaw in Ollama's GGUF metadata parser (readGGUFV1String) that directly triggers application panic or resource exhaustion, matching T1499.004 Application or System Exploitation for DoS.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SI-10 directly addresses the improper input validation of untrusted GGUF metadata string lengths in readGGUFV1String, preventing panic or resource exhaustion.
SI-2 ensures timely flaw remediation by patching the specific vulnerability in Ollama's GGUF parsing code.
SC-5 implements denial-of-service protections to mitigate resource exhaustion from malicious GGUF metadata over the network.