CVE-2026-66753

tiny-http 0.12.0 HTTP Response Splitting via Header Injection

Published Jul 28, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
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.

Analysis

AI-generated

Technical impact

tiny‑http versions up to 0.12.0 parse and serialize HTTP headers without checking for carriage return (0x0D) and line feed (0x0A) characters, allowing an attacker to inject these bytes into any header value on both request and response sides. The resulting HTTP header injection can be used for response splitting, cache poisoning, session fixation through Set‑Cookie injection, overriding critical security headers, and request smuggling against back‑end services that tolerate line feeds. The base weakness is identified as CWE‑113, which directly impacts the integrity of HTTP traffic and can lead to confidentiality, integrity, and availability violations for users of the affected application.

Affected Systems

The vulnerability affects the tiny‑http library provided by the vendor "tiny-http:tiny-http" and specifically applies to releases through 0.12.0. No other affected versions are listed in the current data.

Risk and Exploitability

The CVSS score of 6.3 indicates moderate severity. The EPSS score is less than 1 %, suggesting a low likelihood of exploitation at the time of analysis. The vulnerability is not currently indexed in CISA’s KEV catalog. Based on the description, the likely attack vector is a remote attacker sending a crafted HTTP request that includes CR‑LF sequences in header values, triggering a split response that can be leveraged for the aforementioned attacks. No additional exploitation prerequisites beyond sending the malicious request are noted in the data.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Check the vendor's website or repository for a patched release or contact the vendor for an update.
  • Configure any custom header handling code to reject CR and LF characters before adding them to request or response headers.
  • Use a reverse proxy or gateway that sanitizes or encodes CR and LF characters in HTTP headers to mitigate risks while a patch is applied.

Generated by OpenCVE AI on August 3, 2026 at 14:51 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Tiny-http Project
Tiny-http Project tiny-http
CPEs cpe:2.3:a:tiny-http_project:tiny-http:*:*:*:*:*:node.js:*:*
Vendors & Products Tiny-http Project
Tiny-http Project tiny-http
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Tinyhttpd
Tinyhttpd tinyhttpd
Vendors & Products Tinyhttpd
Tinyhttpd tinyhttpd
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}

Type Values Removed Values Added
Description 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.
Title tiny-http 0.12.0 HTTP Response Splitting via Header Injection
Weaknesses CWE-113
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses
  • CWE-113

    Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Aug 14, 2026, 4:50 PM
Reserved
Jul 27, 2026, 4:27 PM
Status
Deferred
Published
Jul 28, 2026, 4:20 PM
Modified
Jul 30, 2026, 8:03 PM