What’s Vulnerable › Vulnerabilities

CVE-2026-85077: Sanic: HTTP response header injection via missing CR/LF validation in Sanic HTTP/1.1 responses

• Severity: high (CVSS 8.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-09-24
• Weakness: CWE-113

Description

Sanic is an opensource python web server/framework. Prior to version 24.12.1, and in version 25.12.0, the HTTP/1.1 response pipeline in sanic/response/types.py serializes response header names and values without rejecting carriage-return or line-feed characters. Applications that place attacker-controlled data in response.headers, file(..., filename=...), or cookie path and domain attributes can therefore emit injected headers and may split responses. Depending on application and proxy behavior, this can enable session fixation through injected cookies, cache poisoning, or security-header corruption. This issue is fixed in versions 24.12.1 and 25.12.1.

Affected products

• sanic-org sanic: before 24.12.1; from 25.12.0, < 25.12.1

References

• https://github.com/sanic-org/sanic/commit/47349d689d65fa1907977ac100e867894aeafb22
• https://github.com/sanic-org/sanic/commit/9a95bb1c187558949606b915f5162c15f2db781b
• https://github.com/sanic-org/sanic/commit/a332796506c7c588b6930b02a8886e43eb8ea8d6
• https://github.com/sanic-org/sanic/pull/3164
• https://github.com/sanic-org/sanic/pull/3165
• https://github.com/sanic-org/sanic/releases/tag/v24.12.1
• https://github.com/sanic-org/sanic/releases/tag/v25.12.1
• https://github.com/sanic-org/sanic/security/advisories/GHSA-m64h-22vf-48wm

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