Auth bypass in Livehelperchat Live Helper Chat
CVE-2026-27954
Live Helper Chat is an open-source application that enables live support websites. In versions up to and including 4.52, three chat action endpoints (holdaction.php, blockuser.php, and transferchat.php) load chat objects by ID without calling `erLhcoreClassChat::hasAccessToRead()`, allowing operators to act on chats in departments they are not assigned to. Operators with the relevant role permissions (holduse, allowblockusers, allowtransfer) can hold, block users from, or transfer chats in departments they are not assigned to. This is a horizontal privilege escalation within one organization. As of time of publication, no known patched versions are available.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (24.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Livehelperchat Live Helper Chat
- Livehelperchat — versions <= 4.52
Weakness classification (CWE)
References
- github.com/LiveHelperChat/livehelperchat/security/advisories/GHSA-87wc-2p86-h3w7 (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-27954?
- CVE-2026-27954 is a medium-severity vulnerability in Livehelperchat Live Helper Chat, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-02-26.
- How severe is CVE-2026-27954?
- Medium severity. CVSS v3 base score is 6.5 out of 10.