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.
History

Wed, 25 Feb 2026 20:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
CPEs cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*

Wed, 25 Feb 2026 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Gofiber
Gofiber fiber
Vendors & Products Gofiber
Gofiber fiber

Tue, 24 Feb 2026 22:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 24 Feb 2026 21:30:00 +0000

Type Values Removed Values Added
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.
Title Fiber is Vulnerable to Denial of Service via Flash Cookie Unbounded Allocation
Weaknesses CWE-789
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-02-24T21:11:17.804Z

Updated: 2026-02-24T21:37:33.970Z

Reserved: 2026-02-06T21:08:39.131Z

Link: CVE-2026-25899

cve-icon Vulnrichment

Updated: 2026-02-24T21:37:28.560Z

cve-icon NVD

Status : Analyzed

Published: 2026-02-24T22:16:31.613

Modified: 2026-02-25T20:31:50.943

Link: CVE-2026-25899

cve-icon Redhat

No data.