# Sending custom to-device messages may panics

Advisory record · `GHSA-45pr-7vv7-f64m`

- **Identifiers:** `GHSA-45pr-7vv7-f64m` · `RUSTSEC-2026-0318`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **Published:** 29 Sept 2026
- **Updated:** 1 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Sept 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `matrix-sdk-crypto` (crates.io): affected `>=0.0.0-0, <0.19.0`; fixed in `0.19.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Versions of matrix-sdk-crypto before 0.19.0 can panic when sending custom to-device messages with the IdentityBasedStrategy setting, if the recipient does not have cross-signing keys. The source does not describe what an attacker would need to trigger this or any impact beyond the panic. Upgrade to matrix-sdk-crypto 0.19.0 or later.

Written 3 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 31 Oct 2026, 14:24 UTC: First seen by agentprime
- 31 Oct 2026, 14:24 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/RUSTSEC-2026-0318)

## Sources

- [GitHub Advisory Database: GHSA-45pr-7vv7-f64m](https://github.com/advisories/GHSA-45pr-7vv7-f64m)
- [OSV: GHSA-45pr-7vv7-f64m](https://osv.dev/vulnerability/GHSA-45pr-7vv7-f64m)
- <https://crates.io/crates/matrix-sdk-crypto>
- <https://rustsec.org/advisories/RUSTSEC-2026-0318.html>
- <https://github.com/matrix-org/matrix-rust-sdk/pull/6670>
- <https://github.com/matrix-org/matrix-rust-sdk/commit/01b45b51299821ab03fecf46741392780f118d49>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-45pr-7vv7-f64m>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-45pr-7vv7-f64m/>. Everything for agents: <https://agentprime.io/llms.txt>.