Is CVE-2026-9540 in the CISA KEV catalog?

No. CVE-2026-9540 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-9540?

CVE-2026-9540 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-9540?

CVE-2026-9540 has an EPSS score of 0.43% (34th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-9540?

No published fix for CVE-2026-9540 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-9540

MEDIUM

5.3

CVSS v3

NVD

Description

A vulnerability was identified in vllm-project vllm 0.19.0. This issue affects some unknown processing of the component OpenAI-compatible Serving Path. Such manipulation leads to denial of service. It is possible to launch the attack remotely. The exploit is publicly available and might be used. The pull request to fix this issue awaits acceptance.

CWE-404

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.43%probability of exploitation in 30 days

34thpercentile

Low risk: more likely to be exploited than 34% of all known CVEs.

References

Other references7

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-26.