PatchSiren

PatchSiren cyber security CVE debrief

CVE-2025-71379 vllm CVE debrief

CVE-2025-71379 is a medium-severity vulnerability affecting vLLM, a project with versions >= 0.6.3 and < 0.9.0 that contain multiple regular expression denial of service (ReDoS) vulnerabilities. These vulnerabilities are due to susceptible regex patterns in vllm/lora/utils.py, the phi4mini tool parser, and the OpenAI-compatible serving chat endpoint. An attacker can trigger severe CPU consumption and performance degradation by submitting crafted input with nested or repeated structures, resulting in denial of service. Defenders should assess their exposure and prioritize patching due to the potential for service disruption.

Vendor
vllm
Product
Unknown
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-20
Original CVE updated
2026-06-26
Advisory published
2026-06-20
Advisory updated
2026-06-26

Who should care

Organizations using vLLM versions >= 0.6.3 and < 0.9.0 should prioritize patching to prevent potential denial-of-service attacks. This vulnerability could impact services relying on vLLM for critical operations, especially those with high availability requirements. Developers and administrators of applications built on top of vLLM should assess their exposure and take appropriate measures.

Technical summary

The vulnerability exists in multiple components of vLLM, including vllm/lora/utils.py, the phi4mini tool parser, and the OpenAI-compatible serving chat endpoint. Specifically, the regex patterns in these components are susceptible to catastrophic backtracking when processing crafted input with nested or repeated structures. This can lead to severe CPU consumption and performance degradation, effectively causing a denial of service. The CVSS score for this vulnerability is 5.3, indicating a medium severity level.

Defensive priority

Medium priority due to potential service disruption with CVSS score of 5.3.

Recommended defensive actions

  • Inventory vLLM installations to identify potentially affected versions.
  • Review official advisories and documentation for patching guidance.
  • Apply vendor-supported remediation by updating to a patched version (>= 0.9.0).
  • Implement compensating controls such as input validation and rate limiting.
  • Monitor for suspicious activity and performance degradation.

Evidence notes

The primary evidence for this vulnerability comes from the CVE record and NVD detail pages. The vulnerability affects vLLM versions >= 0.6.3 and < 0.9.0. Defenders should verify the version of vLLM in use and check for official patches or advisories from the vendor. The CVE record and NVD detail provide additional information on the vulnerability's characteristics and potential impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-71379 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-71379

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2025-71379 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-71379

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.