CVE-2026-100647
No exploitation reported by the sources we read.
- Published2026-09-26
- Fixed in0.29.0
- WeaknessCWE-20
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
vLLM versions before 0.29.0 contain a denial-of-service vulnerability in the cache_salt parameter accepted on OpenAI-compatible and Anthropic API endpoints, which lacks maximum length validation and is processed on the single EngineCore scheduler thread. Unauthenticated attackers can send HTTP requests with multi-hundred-megabyte salt values that trigger expensive pickle serialization and SHA-256 hashing, stalling the scheduler thread and denying service to all concurrent requests.
Timeline
dates in UTC- 2026-09-2614:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-100647?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-100647?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 0.29 | < 0.29.0 | 0.29.0 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
vllm: vLLM: Denial of Service via unbounded cache_salt parameter
rhaii/vllm-cpu-rhel9 as a component of Red Hat AI Inference Server · rhaii/vllm-cuda-rhel9 as a component of Red Hat AI Inference Server · rhaii/vllm-gaudi-rhel9 as a component of Red Hat AI Inference Server · +24 more
Fix
- Update Vllm to 0.29.0
- Workaround from the vendor Red Hat Product Security CVE-2026-100647 · 27 productsThere is no vLLM env-var toggle that bounds cache_salt on vulnerable builds. Try to strip or deny cache_salt at the gateway or put Auth + rate limits on OpenAI/Anthropic-compatible endpoints.
- No fix available, says the vendor Red Hat Product Security CVE-2026-100647 · 27 productsFix deferred
Advisories and patches
- github.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS 4.0 vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Published
- 2026-09-26
- Last Modified
- 2026-10-06
- NVD status
- Analyzed
Frequently asked questions
What is CVE-2026-100647?
Is CVE-2026-100647 actively exploited?
What is the CVSS score for CVE-2026-100647?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.