VulnerabilityPublished 26 Oct 2026

CVE-2026-115917: vllm · Permissive Cross-domain Security Policy with Untrusted Domains

Affects vllmSource CVE Database V5

Not known to be exploited · CVSS 3.4 Low : upgrade to 0.32.0 when convenient.

Data as of 26 Oct 2026, 17:57 UTC

CVSS 3.1 base score

3.4Low

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 0.32.0

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade vllm and vllm-project/vllm to 0.32.0.

Affected software

Product	Affected	Fixed in
vllm-projectvllm	Affected <0.32.0	Fixed in 0.32.0
GitHubvllm-project/vllm`pkg:github/vllm-project/vllm`Other threats	Affected <0.32.0	Fixed in 0.32.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade vLLM to version 0.32.0 or later, where the permissive CORS policy is fixed by restricting allowed origins. No additional mitigation is required as the issue is resolved in the official fix.

Description

vLLM versions prior to 0.32.0 have a permissive cross-origin resource sharing (CORS) policy that allows any origin by default. This misconfiguration enables a malicious web page to interact with an unauthenticated vLLM server running on localhost, internal networks, or VPNs, potentially consuming GPU resources and reading responses. The issue is fixed in version 0.32.0.

Impact

An attacker can exploit the permissive CORS policy to make a victim's browser send requests to an unauthenticated vLLM server on localhost or internal networks. This can lead to unauthorized consumption of GPU resources and reading of server responses. However, the impact is limited by the requirement that credentials are disabled by default and bearer token authentication is only exposed to callers already possessing a valid token. The CVSS score is 3.4 (low severity), reflecting limited confidentiality impact and high attack complexity.

Summary

vLLM is an inference and serving engine for large language models. Before version 0.32.0, its OpenAI-compatible server used Starlette CORSMiddleware configured with allowed_origins set to a wildcard by default. This permissive CORS policy allows malicious web pages to send requests from a victim's browser to an unauthenticated vLLM server on localhost or internal networks, accessing endpoints such as GET /v1/models and POST /v1/chat/completions. Although cookie-based CSRF is not applicable due to disabled credentials by default, unauthorized resource consumption and data exposure are possible. The vulnerability is addressed in vLLM version 0.32.0 by restricting the allowed origins.

CWE-942Permissive Cross-domain Security Policy with Untrusted Domains (opens in a new tab)
Variant weaknessOWASP Top 10 A02:2025: Security Misconfiguration (opens in a new tab)
The product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.
Architecture and Design · Operation · Attack Surface Reduction
Define a restrictive Content Security Policy or cross-domain policy file.
Architecture and Design · Operation · Attack Surface Reduction
Avoid using wildcards in the CSP / cross-domain policy file. Any domain matching the wildcard expression will be implicitly trusted, and can perform two-way interaction with the target server.
Architecture and Design · Operation · Environment Hardening
For Flash, modify crossdomain.xml to use meta-policy options such as 'master-only' or 'none' to reduce the possibility of an attacker planting extraneous cross-domain policy files on a server.
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V1.14.1 (opens in a new tab)
V13.4.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 17:44 UTC

WeaknessesCWE-942

Technical details

References

Community reviews

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