tiny-http up to 0.12.0 Header Parsing/Serialization response splitting

Summaryinfo

A vulnerability has been found in tiny-http up to 0.12.0 and classified as critical. This vulnerability affects unknown code of the component Header Parsing/Serialization. Performing a manipulation results in response splitting. This vulnerability is known as CVE-2026-66753. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, was found in tiny-http up to 0.12.0. This affects an unknown part of the component Header Parsing/Serialization. The manipulation with an unknown input leads to a response splitting vulnerability. CWE is classifying the issue as CWE-113. The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

tiny-http through 0.12.0 contains an HTTP header injection vulnerability that allows attackers to inject carriage return (0x0D) and line feed (0x0A) bytes into HTTP header values on both request and response sides due to insufficient validation in header parsing and serialization. Attackers can exploit this injection primitive to perform response splitting, cache poisoning, session fixation via Set-Cookie injection, security header override, and request smuggling against line-feed-tolerant backends.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-66753 since 07/27/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/28/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• tiny-http

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12.0

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

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• 🔒
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