# CVE-2026-63095: Dendrite 0.13.8 Improper Authorization via POST account/3pid/delete Endpoint

> Authenticated users can delete other users' third-party identifier bindings, enabling account takeover via password reset hijacking.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-35h8-2q42-v6f5

## What is CVE-2026-63095?

CVE-2026-63095 is a high-severity missing authorization vulnerability in matrix-org dendrite, published on 17 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Dendrite through 0.13.8 contains an improper authorization vulnerability in the Matrix Client-Server API that allows any authenticated local user to delete third-party identifier bindings belonging to other users by submitting an arbitrary address and medium to the account deletion endpoint without ownership verification. Attackers can exploit the unverified Forget3PID handler to remove a victim's email or MSISDN binding and subsequently rebind the address through an identity server to hijack the victim's password reset flow.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-63095?


## How do I fix CVE-2026-63095?

No fix has been published for CVE-2026-63095 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-63095 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63095 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63095 and fix it if it is affected.

What it is: CVE-2026-63095 is a high-severity missing authorization vulnerability in matrix-org dendrite, published on 17 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63095 exists.

Affected product: matrix-org dendrite. 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-2026-63095/ (Markdown: https://insights.sbomify.com/CVE-2026-63095/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63095
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63095
- OSV: https://osv.dev/vulnerability/CVE-2026-63095

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-63095/
Summaries are generated and may contain mistakes; the official description above is the record.