# CVE-2026-113867: Stanza injection in XMPP chat


- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 20 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-113867, GHSA-7qpm-g2hw-rqrc, UBUNTU-CVE-2026-113867

## What is CVE-2026-113867?

CVE-2026-113867 is a critical vulnerability in Mozilla Thunderbird, published on 20 Oct 2026. 

### Official description

Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would then process as if sent by the user. This could be used to send messages or change contact and subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's chat feature with XMPP accounts. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.

Weakness: CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-113867?


## How do I fix CVE-2026-113867?

Upgrade to a fixed version.

## Is CVE-2026-113867 being exploited?

There is no known exploitation of CVE-2026-113867 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-113867 and fix it if it is affected.

What it is: CVE-2026-113867 is a critical vulnerability in Mozilla Thunderbird, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-113867 in the wild and no public exploit code.

Affected product: Mozilla Thunderbird. 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-2026-113867/ (Markdown: https://insights.sbomify.com/CVE-2026-113867/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-113867
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-113867
- OSV: https://osv.dev/vulnerability/CVE-2026-113867

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-113867/
Summaries are generated and may contain mistakes; the official description above is the record.