TI-2024-26615 Aliases CVE-2024-39691 GHSA-w9mh-5x8j-9754

Malicious Matrix homeserver can leak truncated message content of messages it shouldn't have access to

LOW 21CWE-280Published 2024-07-05 · Updated 2024-08-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: Low · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00498 42nd percentileScored 2026-11-07

Fix Fixed matrix-appservice-irc (matrix-org): 2.0.1matrix-appservice-irc (npm): 2.0.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
matrix-org	matrix-appservice-irc	before 2.0.1	2.0.1	Patch available	CNA
—	matrix-appservice-irc (npm)	before 2.0.1	2.0.1	Patch available	GHSA-w9mh-5x8j-9754

matrix-appservice-irc Vendormatrix-org Affected before 2.0.1 Fixed in 2.0.1 Patch available CNA
matrix-appservice-irc (npm) Vendor— Affected before 2.0.1 Fixed in 2.0.1 Patch available GHSA-w9mh-5x8j-9754

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:matrix:matrix_irc_bridge::::::::	—	—	matrix-org

cpe:2.3:a:matrix:matrix_irc_bridge:*:*:*:*:*:*:*:* Versions — — ·matrix-org

Remediation

Fix · CNA matrix-appservice-irc (matrix-org) Fixed in 2.0.1
Fix · GHSA-w9mh-5x8j-9754 matrix-appservice-irc (npm) Fixed in 2.0.1 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2024-39691
2026-10-03 Alias added: GHSA-w9mh-5x8j-9754

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2024-39691

Other 5

TI-2023-20035 Sydent does not verify email server certificates CVSS 3.1CRITICAL 9.3
TI-2026-45046 Dendrite 0.13.8 SSRF via Unauthenticated Legacy Media Download Endpoint CVSS 4.0MEDIUM 6.9
TI-2026-45045 Dendrite 0.13.8 Improper Authorization via POST account/3pid/delete Endpoint CVSS 4.0HIGH 7.1
TI-2026-45047 Dendrite 0.13.8 syncapi /context Endpoint Post-Leave State Exposure CVSS 4.0MEDIUM 5.3
TI-2023-15617 Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites CVSS 3.1MEDIUM 5.0
TI-2023-20039 matrix-appservice-irc IRC command injection via admin commands containing newlines CVSS 3.1CRITICAL 9.8

See all 115 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences