CVE-2026-85077

Sanic: HTTP response header injection via missing CR/LF validation in Sanic HTTP/1.1 responses

HIGH
8.2
CVSS Score
Published: September 17, 2026 at 02:26 PM UTC
Updated: September 24, 2026 at 09:37 PM UTC
1 product affected across 1 vendorSanic

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Severity
HIGH8.2
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 24.12.1v < 25.12.1
Affected range stops below 24.12.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 25.12.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-113

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