CVE-2026-45056
Sender-binding gaps in to-device messages
Description
The matrix-sdk-crypto crate before 0.16.1 is missing a check for the sender's user ID when decrypting an Olm-encrypted to-device message containing the sender_device_keys property. This could be exploited to spoof the sender of an encrypted to-device message, but only if the attacker colludes with (or is) the homeserver operator.
How to fix CVE-2026-45056
To remediate CVE-2026-45056, upgrade the affected package to a fixed version below.
- crates.io/matrix-sdk-crypto—upgrade to 0.16.1 or later
- crates.io/matrix-sdk-crypto—upgrade to 0.16.1 or later
Is CVE-2026-45056 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-45056.
Affected packages (2)
- >= 0.12.0, < 0.16.1
- >= 0.12.0, < 0.16.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |