What is the CVSS score of CVE-2021-22959?

CVE-2021-22959 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N. EPSS exploitation probability: 2.9%.

Is there a public PoC exploit available for CVE-2021-22959?

Yes, a public proof-of-concept exploit is available for CVE-2021-22959. Prioritise patching immediately. EPSS: 2.9%.

Is there a patch available for CVE-2021-22959?

Yes, a patch is available for CVE-2021-22959. Update the affected software to the latest version immediately.

Llhttp CVE-2021-22959

MEDIUM

HTTP Request/Response Smuggling (CWE-444)

2021-11-15 support@hackerone.com

Request Smuggling Information Disclosure Llhttp Graalvm Debian Linux

6.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.5 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

CVE Published

Nov 15, 2021 - 15:15 nvd

MEDIUM 6.5

DescriptionNVD

The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6.

AnalysisAI

The parser in accepts requests with a space (SP) right after the header name before the colon. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6. Affected products include: Llhttp, Oracle Graalvm, Debian Debian Linux.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.