# CVE-2026-123319: In JetBrains Ktor before 3.6.1 missing Domain attribute validation in client cookie storage allowed cookie injection


- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 6 Nov 2026
- **Updated:** 10 Nov 2026
- **Also known as:** GHSA-2qr9-2f88-gccj

## What is CVE-2026-123319?

CVE-2026-123319 is a low-severity vulnerability in JetBrains Ktor, published on 6 Nov 2026. 

### Official description

In JetBrains Ktor before 3.6.1 missing Domain attribute validation in client cookie storage allowed cookie injection

Weakness: CWE-565 (Reliance on Cookies without Validation and Integrity Checking)

## Which versions are affected by CVE-2026-123319?


## How do I fix CVE-2026-123319?

No fix has been published for CVE-2026-123319 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123319 being exploited?

There is no known exploitation of CVE-2026-123319 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123319 and fix it if it is affected.

What it is: CVE-2026-123319 is a low-severity vulnerability in JetBrains Ktor, published on 6 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123319 in the wild and no public exploit code.

Affected product: JetBrains Ktor. 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-2026-123319/ (Markdown: https://insights.sbomify.com/CVE-2026-123319/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123319
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123319
- OSV: https://osv.dev/vulnerability/CVE-2026-123319

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123319/
Summaries are generated and may contain mistakes; the official description above is the record.