CVE-2026-34755 vLLM Affected by Denial of Service via Unbounded Frame Count in video/jpeg Base64 Processing
Attackers can crash vLLM servers by sending requests with excessive base64-encoded JPEG frames, bypassing frame count limits.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34755?
CVE-2026-34755 is a medium-severity denial of service vulnerability in Vllm Vllm, published on 6 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
vLLM is an inference and serving engine for large language models (LLMs). From 0.7.0 to before 0.19.0, the VideoMediaIO.load_base64() method at vllm/multimodal/media/video.py splits video/jpeg data URLs by comma to extract individual JPEG frames, but does not enforce a frame count limit. The num_frames parameter (default: 32), which is enforced by the load_bytes() code path, is completely bypassed in the video/jpeg base64 path. An attacker can send a single API request containing thousands of comma-separated base64-encoded JPEG frames, causing the server to decode all frames into memory and crash with OOM. This vulnerability is fixed in 0.19.0.
Weakness: CWE-770
Which versions are affected by CVE-2026-34755?
3 open source packages ship an affected version, including vllm. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vllm PyPI | From 0.7.0 | 0.19.0 |
vllm PyPI | From 0.7.0 | 0.19.0 |
vllm PyPI | From 0.7.0 | 0.19.0 |
Products include Vllm Vllm.
How do I fix CVE-2026-34755?
Upgrade vllm to 0.19.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-34755 being exploited?
There is no known exploitation of CVE-2026-34755 in the wild and no public exploit code.
Other vulnerabilities in Vllm Vllm
- CVE-2025-32444 vLLM Vulnerable to Remote Code Execution via Mooncake Integration
- CVE-2026-22778 vLLM leaks a heap address when PIL throws an error
- CVE-2025-47277 vLLM Allows Remote Code Execution via PyNcclPipe Communication Service
- CVE-2024-11041 Remote Code Execution in vllm-project/vllm
- CVE-2026-48746 vLLM: OpenAI auth bypass
Sources
Also known as GHSA-pq5c-rjhq-qp7p, PYSEC-2026-144.