CVE-2026-90878 - Vulnerability Details

- vllm-project vLLM Jinja Template Rendering completions resource consumption

Description

A vulnerability was determined in vllm-project vLLM up to 0.27.1. This affects an unknown part of the file /v1/chat/completions of the component Jinja Template Rendering. This manipulation of the argument chat_template causes resource consumption. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. The pull request to fix this issue awaits acceptance.

Published: 2026-09-15

Score: 5.3 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

A vulnerability was identified in vLLM prior to version 0.27.1 whereby manipulation of the ‘chat_template’ argument within the /v1/chat/completions endpoint can trigger excessive resource consumption during Jinja template rendering. The issue exploits uncontrolled resource usage (CWE‑400) and potential improper handling of unexpected conditions (CWE‑404). If exploited, the server may become unable to process legitimate requests, leading to denial of service and potential availability loss. The flaw is remote and does not require local privilege.

Affected Systems

The affected software is the vllm‑project vLLM library. All versions up to and including 0.27.1 component of vLLM; no specific platform constraints are listed.

Risk and Exploitability

Based on its CVSS score of 5.3, this vulnerability is classified as moderate severity. The EPSS score of < 1% indicates a very low exploitation probability, and it is not listed in the CISA KEV catalog. Attackers can exploit the flaw remotely by submitting crafted chat_template payloads to the /v1/chat/completions endpoint, causing excessive resource consumption during Jinja template rendering. Public exploitation has been disclosed, and active misuse may result in CPU, memory, or other resource exhaustion, potentially leading to denial of service for legitimate users.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

vllm-project

vLLM

affected

Version	Status	Constraints
`0.27.0`	affected	—
`0.27.1`	affected	—

No data.

Vendor Product Confidence Versions

Vllm-project

Vllm

95%

Version	Status	Scheme	Platform
`0.27.0`	affected	semver	—
`0.27.1`	affected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the vendor patch as soon as it is released; the upstream fix is pending acceptance.
If a patch is not yet available, enforce strict input validation and size limits on the chat_template parameter to mitigate uncontrolled resource consumption (CWE‑400) and unchecked inputs (CWE‑606).
Consider temporarily disabling the /v1/chat/completions endpoint or the Jinja template rendering feature until a patch is applied to limit resource usage (CWE‑400, CWE‑404).
Implement application‑level resource quotas or rate limiting for the endpoint to prevent server overload (CWE‑400).

Generated by OpenCVE AI on September 17, 2026 at 18:48 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

Access Vector Network

Access Complexity Low

Authentication Single

Confidentiality Impact None

Integrity Impact None

Availability Impact Partial

This CVE is not in the KEV list.

The EPSS score is 0.00533.

Exploitation poc

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/vllm-project/vllm/
https://github.com/vllm-project/vllm/issues/52025
https://github.com/vllm-project/vllm/pull/52163
https://nvd.nist.gov/vuln/detail/CVE-2026-90878
https://vuldb.com/cve/CVE-2026-90878
https://vuldb.com/submit/927901
https://vuldb.com/vuln/403472
https://vuldb.com/vuln/403472/cti
https://www.cve.org/CVERecord?id=CVE-2026-90878

History

Tue, 15 Sep 2026 15:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Tue, 15 Sep 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-606
References		https://nvd.nist.gov/vuln/detail/CVE-2026-90878 https://www.cve.org/CVERecord?id=CVE-2026-90878
Metrics	threat_severity `None`	threat_severity `Moderate`

Tue, 15 Sep 2026 04:30:00 +0000

Type	Values Removed	Values Added
Description		A vulnerability was determined in vllm-project vLLM up to 0.27.1. This affects an unknown part of the file /v1/chat/completions of the component Jinja Template Rendering. This manipulation of the argument chat_template causes resource consumption. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. The pull request to fix this issue awaits acceptance.
Title		vllm-project vLLM Jinja Template Rendering completions resource consumption
First Time appeared		Vllm-project Vllm-project vllm
Weaknesses		CWE-400 CWE-404
CPEs		cpe:2.3:a:vllm-project:vllm::::::::
Vendors & Products		Vllm-project Vllm-project vllm
References		https://github.com/vllm-project/vllm/ https://github.com/vllm-project/vllm/issues/52025 https://github.com/vllm-project/vllm/pull/52163 https://vuldb.com/cve/CVE-2026-90878 https://vuldb.com/submit/927901 https://vuldb.com/vuln/403472 https://vuldb.com/vuln/403472/cti
Metrics		cvssV2_0 `{'score': 4, 'vector': 'AV:N/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR'}` cvssV3_0 `{'score': 4.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R'}` cvssV3_1 `{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R'}` cvssV4_0 `{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P'}`

Subscriptions

Vllm-project Vllm

MITRE

Status: PUBLISHED

Assigner: VulDB

Published: 2026-09-15T04:15:11.051Z

Updated: 2026-09-15T13:54:06.533Z

Reserved: 2026-09-14T07:16:13.062Z

Link: CVE-2026-90878

Vulnrichment

Updated: 2026-09-15T13:41:59.930Z

NVD

Status : Deferred

Published: 2026-09-15T05:16:59.420

Modified: 2026-09-15T14:37:14.523

Link: CVE-2026-90878

Redhat

Severity : Moderate

Publid Date: 2026-09-15T04:15:11Z

Links: CVE-2026-90878 - Bugzilla

OpenCVE Enrichment

Updated: 2026-09-17T21:00:17Z

Weaknesses

CWE-400
Uncontrolled Resource Consumption
CWE-404
Improper Resource Shutdown or Release
CWE-606
Unchecked Input for Loop Condition

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

Access Vector Network

Access Complexity Low

Authentication Single

Confidentiality Impact None

Integrity Impact None

Availability Impact Partial

Exploitation poc

Automatable no

Technical Impact partial

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object