Better Messages <= 2.15.33 - Unauthenticated Information Exposure Spoofing via 'X-Real-IP' Header via /guests/register

published 2026-09-19 51 d ago modified 2026-09-21 48 d ago also EUVD-2026-83478

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits: 0; none known

The Better Messages – Chat Rooms, Group Chat, Private Messages & AI Chat Bots plugin for WordPress is vulnerable to Information Exposure by Spoofing in all versions up to, and including, 2.15.33. This is due to the `is_ai_bot_user()` function identifying privileged internal AI bot accounts by performing a prefix check for `'ai-chat-bot-'` against a guest record's stored IP address, which is populated verbatim from the client-controlled `X-Real-IP` request header during unauthenticated guest registration. This makes it possible for unauthenticated attackers to register a guest identity that the plugin treats as its own internal AI bot, bypassing the per-room role allowlist, draft-status check, and join filters — which are all short-circuited by the bot check in `user_can_join()` and `user_can_read()` — to join administrator-restricted chat rooms, post messages into them, and read the private message history of other users.

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 50 d ago (2026-09-19)

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

wordplus Better Messages – Chat Rooms, Group Chat, Private Messages & AI Chat Bots

Classification

Weakness

CWE-287 Improper Authentication

Technology feeds

WordPress rss critical rss

References

Sources

CVE List CVE-2026-89093
NVD CVE-2026-89093

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary