CVE-2026-66746
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2026-66746 is indexed in GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation even though it is not (yet) in the CISA KEV catalog.
Rouille 0.4.0 through 3.6.2 contains an HTTP response splitting vulnerability that allows remote attackers to inject arbitrary response headers by embedding carriage return (0x0D) or line feed (0x0A) bytes into attacker-controlled input. Attackers can exploit percent-decoded query parameters reflected into response headers or inject bare LF characters into Cookie header values that are interpolated directly into Set-Cookie response headers, enabling cache poisoning, session fixation, and security header override attacks such as bypassing CSP or CORS policies.
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Exploitation outlook
- Low exploitation risk0.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2026-66746 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (1)
External references
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[](https://www.csirts.com/cve/CVE-2026-66746)