NULL pointer dereference in Sdelements Lets-Chat
CVE-2026-66749
Let's Chat 0.4.0 through 0.4.8 contains a null dereference vulnerability that allows authenticated attackers to crash the server by supplying a valid 24-character hex string room parameter that matches no document in the database. Attackers can send a crafted GET /messages request causing an uncaught TypeError in an asynchronous Mongoose callback that terminates the Node.js server process, with the same defect reachable through multiple code paths including the socket.io interface.
EPSS: 0.003 (23.7th percentile) — read the EPSS interpretation.
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:N/A:H.
Affected products
- Sdelements Lets-chat — versions 0.4.0, 84981a6d2534445c00ea4e095c934e46943c0b1d
Weakness classification (CWE)
Public proof-of-concept exploits
References
- disclosure@vulncheck.com (technical-description, exploit)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-66749?
- CVE-2026-66749 is a medium-severity vulnerability in Sdelements Lets-Chat, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-07-28.
- How severe is CVE-2026-66749?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2026-66749 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.