# CVE-2026-7141: vLLM KV Block kv_cache_interface.py has_mamba_layers uninitialized resource

> Uninitialized resource in vLLM KV block handler may cause undefined behavior, though disputed as benign variance.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Apr 2026
- **Updated:** 25 Aug 2026
- **Also known as:** GHSA-x368-4g9h-fvv4, PYSEC-2026-2306

## What is CVE-2026-7141?

CVE-2026-7141 is a medium-severity vulnerability in Vllm Vllm, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in vLLM up to 0.19.0. The affected element is the function has_mamba_layers of the file vllm/v1/kv_cache_interface.py of the component KV Block Handler. Performing a manipulation results in uninitialized resource. It is possible to initiate the attack remotely. The attack is considered to have high complexity. The exploitability is described as difficult. The exploit has been made public and could be used. The existence of this vulnerability is still disputed at present. The proposed patch did not fix the issue. A 3rd party explains: "The divergence could be explained by a benign and expected vLLM behavior where vLLM server could group concurrent requests together resulting in different input shapes based on varying request arrival time. The differences in grouped input shapes could call different kernels with could produce difference results due to rounding and differences in order of operations. There is an environment variable VLLM_BATCH_INVARIANT=1 for users that desire to have deterministic output with temperature 0.0."

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-7141?

3 open source packages ship an affected version, including vllm. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `vllm` | PyPI | All versions | 0.19.1 |
| `vllm` | PyPI | All versions | 0.19.1 |
| `vllm` | PyPI | All versions | 0.19.1 |

Products: Vllm Vllm.

## How do I fix CVE-2026-7141?

Upgrade vllm to 0.19.1 or later.

## Is CVE-2026-7141 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-7141 exists.

## Other vulnerabilities in Vllm Vllm

- [CVE-2025-32444](https://insights.sbomify.com/CVE-2025-32444/): vLLM Vulnerable to Remote Code Execution via Mooncake Integration (critical 10.0)
- [CVE-2026-22778](https://insights.sbomify.com/CVE-2026-22778/): vLLM leaks a heap address when PIL throws an error (critical 9.8)
- [CVE-2025-47277](https://insights.sbomify.com/CVE-2025-47277/): vLLM Allows Remote Code Execution via PyNcclPipe Communication Service (critical 9.8)
- [CVE-2024-11041](https://insights.sbomify.com/CVE-2024-11041/): Remote Code Execution in vllm-project/vllm (critical 9.8)
- [CVE-2026-48746](https://insights.sbomify.com/CVE-2026-48746/): vLLM: OpenAI auth bypass (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-7141 and fix it if it is affected.

What it is: CVE-2026-7141 is a medium-severity vulnerability in Vllm Vllm, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-7141 exists.

Affected packages and fixed versions:
- vllm (PyPI): affected all versions; fixed in 0.19.1
- vllm (PyPI): affected all versions; fixed in 0.19.1
- vllm (PyPI): affected all versions; fixed in 0.19.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-7141/ (Markdown: https://insights.sbomify.com/CVE-2026-7141/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-7141
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-7141
- OSV: https://osv.dev/vulnerability/CVE-2026-7141

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-7141/
Summaries are generated and may contain mistakes; the official description above is the record.