CVE-2024-39691 – matrix-appservice-irc

Package

Manager: npm
Name: matrix-appservice-irc
Vulnerable Version: >=0 <2.0.1

Severity

Level: Medium

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N

EPSS: 0.00086 pctl0.25769

Details

Malicious Matrix homeserver can leak truncated message content of messages it shouldn't have access to ### Impact The fix for GHSA-wm4w-7h2q-3pf7 / [CVE-2024-32000](https://www.cve.org/CVERecord?id=CVE-2024-32000) included in matrix-appservice-irc 2.0.0 relied on the Matrix homeserver-provided timestamp to determine whether a user has access to the event they're replying to when determining whether or not to include a truncated version of the original event in the IRC message. Since this value is controlled by external entities, a malicious Matrix homeserver joined to a room in which a matrix-appservice-irc bridge instance (before version 2.0.1) is present can fabricate the timestamp with the intent of tricking the bridge into leaking room messages the homeserver should not have access to. ### Patches matrix-appservice-irc 2.0.1 [drops the reliance](https://github.com/matrix-org/matrix-appservice-irc/pull/1804) on `origin_server_ts` when determining whether or not an event should be visible to a user, instead tracking the event timestamps internally. ### Workarounds It's possible to limit the amount of information leaked by setting a reply template that doesn't contain the original message. See [these lines](https://github.com/matrix-org/matrix-appservice-irc/blob/d5d67d1d3ea3f0f6962a0af2cc57b56af3ad2129/config.sample.yaml#L601-L604) in the configuration file. ### References - Patch: https://github.com/matrix-org/matrix-appservice-irc/pull/1804 ### For more information If you have any questions or comments about this advisory, please email us at [security at matrix.org](mailto:security@matrix.org).

Metadata

Created: 2024-07-05T20:06:06Z
Modified: 2024-07-05T21:37:31Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/07/GHSA-w9mh-5x8j-9754/GHSA-w9mh-5x8j-9754.json
CWE IDs: ["CWE-280", "CWE-755"]
Alternative ID: GHSA-w9mh-5x8j-9754
Finding: F159
Auto approve: 1