CVE-2026-25899
Fiber is Vulnerable to Denial of Service via Flash Cookie Unbounded Allocation
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-789 |
| Vendor | gofiber |
| Product | fiber |
| Published | Feb 24, 2026 |
| Last Updated | Feb 24, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
gofiber / fiber
>= 3.0.0, < 3.1.0