CVE-2024-39691
Description
matrix-appservice-irc is a Node.js IRC bridge for the Matrix messaging protocol. The fix for GHSA-wm4w-7h2q-3pf7 / 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. matrix-appservice-irc 2.0.1 drops the reliance on origin_server_ts when determining whether or not an event should be visible to a user, instead tracking the event timestamps internally. As a workaround, it's possible to limit the amount of information leaked by setting a reply template that doesn't contain the original message.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
matrix-appservice-ircnpm | < 2.0.1 | 2.0.1 |
Patches
11835e047f269Don't use origin_server_ts when tracking joins, use bridge-time instead (#1804)
2 files changed · +2 −1
changelog.d/1804.misc+1 −0 added@@ -0,0 +1 @@ +Don't use origin_server_ts when tracking joins, use bridge-time instead.
src/bridge/MatrixHandler.ts+1 −1 modified@@ -414,7 +414,7 @@ export class MatrixHandler { */ private _onMemberEvent(req: BridgeRequest, event: OnMemberEventData) { if (event.content.membership === 'join') { - this.memberJoinTs.set(`${event.room_id}/${event.state_key}`, event.origin_server_ts ?? Date.now()); + this.memberJoinTs.set(`${event.room_id}/${event.state_key}`, Date.now()); } else { this.memberJoinTs.delete(`${event.room_id}/${event.state_key}`);
Vulnerability mechanics
Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
6- github.com/advisories/GHSA-w9mh-5x8j-9754ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2024-39691ghsaADVISORY
- github.com/matrix-org/matrix-appservice-irc/blob/d5d67d1d3ea3f0f6962a0af2cc57b56af3ad2129/config.sample.yamlnvdWEB
- github.com/matrix-org/matrix-appservice-irc/commit/1835e047f269001054be4c68867797aa12372a0fnvdWEB
- github.com/matrix-org/matrix-appservice-irc/pull/1804nvdWEB
- github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-w9mh-5x8j-9754nvdWEB
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