CVE-2026-25899
Last modified
CVE-2026-25899 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Fiber is an Express inspired web framework written in Go. In versions on the v3 branch prior to 3.1.0, the use of the `fiber_flash` cookie can force an unbounded allocation on any server. EPSS estimates a 0.40% chance of exploitation in the next 30 days.
Description
Fiber is an Express inspired web framework written in Go. In versions on the v3 branch prior to 3.1.0, the use of the `fiber_flash` cookie can force an unbounded allocation on any server. A crafted 10-character cookie value triggers an attempt to allocate up to 85GB of memory via unvalidated msgpack deserialization. No authentication is required. Every GoFiber v3 endpoint is affected regardless of whether the application uses flash messages. Version 3.1.0 fixes the issue.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Gofiber | Fiber | >= 3.0.0, < 3.1.0 |
References
- https://github.com/gofiber/fiber/releases/tag/v3.1.0Release Notes
- https://github.com/gofiber/fiber/security/advisories/GHSA-2mr3-m5q5-wgp6Exploit, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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