CVE-2026-41523

vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution

HIGH
7.5
CVSS Score
Published: June 22, 2026 at 10:18 PM UTC
Updated: October 25, 2026 at 11:10 PM UTC
3 products affected across 2 vendorsvLLMOpenShift AIAI Inference Server

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Severity
HIGH7.5
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

vLLM is an inference and serving engine for large language models (LLMs). Prior to 0.22.0, an assert-based security check in vLLM's activation function loading allows any unauthenticated attacker to achieve arbitrary code execution on the server by publishing a malicious HuggingFace model, when vLLM runs in Python optimized mode (python -O or PYTHONOPTIMIZE=1). This vulnerability is fixed in 0.22.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.22.0
Affected range stops below 0.22.0, so it looks safe — our inference, not a vendor statement
All versions
Vendor states this is fixed in 1782951012 (unaffected)
Vendor states this is fixed in 1782951244 (unaffected)
Vendor states this is fixed in 1787151769 (unaffected)
Vendor states this is fixed in 1787151771 (unaffected)
Vendor states this is fixed in 1787151774 (unaffected)
Vendor states this is fixed in 1787151840 (unaffected)
Vendor states this is fixed in 1787161382 (unaffected)
Vendor states this is fixed in 1787161803 (unaffected)
Vendor states this is fixed in 1787860580 (unaffected)
Vendor states this is fixed in 1787884873 (unaffected)
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (20)

x_refsource_CONFIRMExploitThird Party Advisory
Source: cverecord
https://github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r
x_refsource_MISCThird Party Advisory
Source: cverecord
https://huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-41523
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2491582
Vendor Advisoryx_refsource_REDHAT
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:36005
Vendor Advisoryx_refsource_REDHAT
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:36006

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-94CWE-617

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