CVE-2026-71486

vLLM: Derender endpoints decode caller-supplied GenerateResponse token IDs without output bounds

MEDIUM
4.3
CVSS Score
Published: August 17, 2026 at 08:13 PM UTC
Updated: October 23, 2026 at 04:10 PM UTC
1 product affected across 1 vendorvLLM

Using vllm by vllm-project?

Get instant alerts when new vulnerabilities affect vllm - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the /v1/completions/derender and /v1/chat/completions/derender endpoints accept caller-supplied GenerateResponse objects whose generate_responses, choices, token_ids, prompt_logprobs, logprobs.content, top_logprobs, and routed_experts structures are processed by OnlineDerenderer and tokenizer.decode before max_model_len, max_tokens, max_num_seqs, or response-size limits are enforced, allowing an authenticated API client to consume excessive CPU and memory and produce oversized responses. This issue is fixed in version 0.26.0.

Affected

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

v < 0.26.0
Affected range stops below 0.26.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitVendor AdvisoryMitigation
Source: cverecord
https://github.com/vllm-project/vllm/security/advisories/GHSA-8737-qx52-hjff
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/vllm-project/vllm/pull/47260
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/vllm-project/vllm/releases/tag/v0.26.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

4.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400CWE-770

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card