# CVE-2026-90555 — vllm-project vLLM

> As of 2026-09-12, CVE-2026-90555 is a MEDIUM-severity vulnerability in vllm-project vLLM, CVSS v3.1 6.5, EPSS 0.2% (19.4th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-90555 as of 2026-09-12; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-12

## What is CVE-2026-90555?

vLLM versions before 0.28.0 fail to validate audio sample rate headers in the transcription endpoint, allowing authenticated clients to bypass duration checks. Attackers can submit forged FLAC headers with inflated sample rates to trigger excessive memory allocation and crash the API server process affecting all tenants.

The record classifies CVE-2026-90555 under weakness class [CWE-409](https://cwe.mitre.org/data/definitions/409.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 23 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 6.5 — MEDIUM (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **CVSS v4.0 base score:** 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 19.4% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-12

## Is CVE-2026-90555 being exploited?

It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [vllm-project](https://intel.threadlinqs.com/vendors/vllm-project): vLLM

## How to fix CVE-2026-90555

No vendor patch reference has been recorded for CVE-2026-90555 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-90555

No threat campaign in the Threadlinqs corpus currently references CVE-2026-90555, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-09-14.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/vllm-project/vllm/security/advisories/GHSA-99f2-hwrc-gvq8)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/vllm-before-0.28.0-denial-of-service-via-audio-header)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-90555
Full detection coverage and IOCs for threats exploiting CVE-2026-90555 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp