PatchTheCVECVE-2026-94623: vLLM through 0.29.0 contains a denial of service vulnerability in the NIXL connector's prefix caching implemen
CVE-2026-94623 is a high-severity flaw (CVSS 7.5) affecting vllm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
vLLM through 0.29.0 contains a denial of service vulnerability in the NIXL connector's prefix caching implementation that fails to properly validate block counts across multi-prompt completion requests in prefill/decode disaggregated deployments. Attackers can trigger an assertion failure in NixlBaseConnectorWorker._apply_prefix_caching by submitting completion requests with multiple prompts of varying lengths, causing the decode worker to termin
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.6% (top 50%) |
| CISA exploited list | No |
| Weakness | CWE-617 |
| Published | 2026-09-21 |
| Last modified | 2026-09-29 |
Last updated 2026-09-29 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-94623?
vllm: upgrade to newer than 0.29.0. Exact commands for each OS are on this page.
Is CVE-2026-94623 being exploited?
CVE-2026-94623 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-94623 affect?
CVE-2026-94623 affects vllm. Severity is high (CVSS 7.5). vLLM through 0.29.0 contains a denial of service vulnerability in the NIXL connector's prefix caching implementation that fails to properly validate block counts across multi-prompt completion requests in prefill/decode disaggregated deploy
How urgent is CVE-2026-94623?
Priority 44/100. High severity; Remotely exploitable, no login, no user action
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