Reported

November 6, 2026

Issued

November 6, 2026

Package

vodozemac (crates.io)

Type

Vulnerability

Categories

• memory-exposure

Aliases

• GHSA-v27v-f96q-qhjq

References

• https://github.com/matrix-org/vodozemac/pull/446

Patched

• >=0.11.2

Description

In version 0.11.1 and earlier of vodozemac, the Olm root key ratchet did not zeroize its HKDF output after use. Each ratchet step left a copy of the new root key and chain key in freed heap memory.

Impact

An attacker who can read the process's memory, for example through a separate memory-disclosure bug, a core dump, or swapped-out pages, may recover root keys and chain keys from earlier ratchet steps. A leaked chain key allows decrypting the messages in that chain, weakening Olm's forward secrecy for affected sessions.

Advisory available under CC0-1.0 license.