CVE-2025-48956
vLLM API endpoints vulnerable to Denial of Service Attacks
vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.10.1.1, a Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. This vulnerability is fixed in 0.10.1.1.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
vLLM API endpoints vulnerable to Denial of Service Attacks
vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.10.1.1, a Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. This vulnerability is fixed in 0.10.1.1.
- Record
CVE-2025-48956- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2025-25446
7.5
vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.10.1.1, a Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. This vulnerability is fixed in 0.10.1.1.
- Record
EUVD-2025-25446- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-rxc4-3w6r-4v47
7.5
vllm API endpoints vulnerable to Denial of Service Attacks
Summary
A Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user.
Details
The vulnerability leverages the abuse of HTTP headers. By setting a header such as X-Forwarded-For to a very large value like ("A" * 5_800_000_000), the server's HTTP parser or application logic may attempt to load the entire request into memory, overwhelming system resources.
Impact
What kind of vulnerability is it? Who is impacted? Type of vulnerability: Denial of Service (DoS)
Resolution
Upgrade to a version of vLLM that includes appropriate HTTP limits by deafult, or use a proxy in front of vLLM which provides protection against this issue.
- Record
GHSA-rxc4-3w6r-4v47- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
7.5
vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.10.1.1, a Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. This vulnerability is fixed in 0.10.1.1.
- Record
CVE-2025-48956- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
7.5
vLLM API endpoints vulnerable to Denial of Service Attacks
vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.10.1.1, a Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. This vulnerability is fixed in 0.10.1.1.
- Record
CVE-2025-48956- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVGHSA-rxc4-3w6r-4v47
7.5
vllm API endpoints vulnerable to Denial of Service Attacks
Summary
A Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user.
Details
The vulnerability leverages the abuse of HTTP headers. By setting a header such as X-Forwarded-For to a very large value like ("A" * 5_800_000_000), the server's HTTP parser or application logic may attempt to load the entire request into memory, overwhelming system resources.
Impact
What kind of vulnerability is it? Who is impacted? Type of vulnerability: Denial of Service (DoS)
Resolution
Upgrade to a version of vLLM that includes appropriate HTTP limits by deafult, or use a proxy in front of vLLM which provides protection against this issue.
- Record
GHSA-rxc4-3w6r-4v47- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVPYSEC-2026-2021
7.5
vllm API endpoints vulnerable to Denial of Service Attacks
Summary
A Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user.
Details
The vulnerability leverages the abuse of HTTP headers. By setting a header such as X-Forwarded-For to a very large value like ("A" * 5_800_000_000), the server's HTTP parser or application logic may attempt to load the entire request into memory, overwhelming system resources.
Impact
What kind of vulnerability is it? Who is impacted? Type of vulnerability: Denial of Service (DoS)
Resolution
Upgrade to a version of vLLM that includes appropriate HTTP limits by deafult, or use a proxy in front of vLLM which provides protection against this issue.
- Record
PYSEC-2026-2021- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
vllmPyPI |
0.1.0 up to 0.10.1.1 | 0.10.1.1 |
vllmPyPI |
0.1.0 up to 0.10.1.1, plus listed versions 0.1.10.1.20.1.30.1.40.1.5 Show 45 moreShow less0.1.60.1.70.10.00.10.10.2.00.2.10.2.1.post10.2.20.2.30.2.40.2.50.2.60.2.70.3.00.3.10.3.20.3.30.4.00.4.0.post10.4.10.4.20.4.30.5.00.5.0.post10.5.10.5.20.5.30.5.3.post10.5.40.5.50.6.00.6.10.6.1.post10.6.1.post20.6.20.6.30.6.3.post10.6.40.6.4.post10.6.50.6.60.6.6.post10.7.00.7.10.7.2 |
0.10.1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-48956 is a high vulnerability (CVSS 7.5) in Vllm, published August 21, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.56%, the 47th percentile. Fixed in vllm 0.10.1.1.
References
github.com/vllm-project/vllm/security/advisories/GHSA-rxc4-3w6r-4v47
github.com/vllm-project/vllm/pull/23267
github.com/vllm-project/vllm/commit/d8b736f913a59117803d6701521d2e4861701944
nvd.nist.gov/vuln/detail/CVE-2025-48956
github.com/advisories/GHSA-rxc4-3w6r-4v47
github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-2021.yaml
github.com/vllm-project/vllm
pypi.org/project/vllm
github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48956.json
Left out here: 12 versions. The JSON record has them.