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

> Attackers can inject headers into Sanic HTTP responses via missing CR/LF validation, enabling session fixation or cache poisoning.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-m64h-22vf-48wm

## What is CVE-2026-85077?

CVE-2026-85077 is a high-severity vulnerability in sanic-org sanic, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-113 (Improper Neutralization of CRLF Sequences in HTTP Headers)

## Which versions are affected by CVE-2026-85077?


## How do I fix CVE-2026-85077?

No fix has been published for CVE-2026-85077 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85077 being exploited?

There is no known exploitation of CVE-2026-85077 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85077 and fix it if it is affected.

What it is: CVE-2026-85077 is a high-severity vulnerability in sanic-org sanic, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-85077 in the wild and no public exploit code.

Affected product: sanic-org sanic. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-85077/ (Markdown: https://insights.sbomify.com/CVE-2026-85077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85077
- OSV: https://osv.dev/vulnerability/CVE-2026-85077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85077/
Summaries are generated and may contain mistakes; the official description above is the record.