6.5Medium
CVE-2026-90927
filebrowser through 2.63.23 fails to limit WebSocket message size in the /api/command handler before checking permissions, allowing authenticated users to buffer arbitrarily large messages. Attackers can send oversized WebSocket messages to exhaust server heap memory and cause denial of service regardless of EnableExec setting or Execute permission.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 16% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 6.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H- CVSS v4
- 7.1
- Weakness
- CWE-400
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-14
- Last modified
- 2026-09-16
- Sources
- NVD