Is CVE-2026-25899 in the CISA KEV catalog?

No. CVE-2026-25899 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-25899?

CVE-2026-25899 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-25899?

CVE-2026-25899 has an EPSS score of 0.40% (31th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-25899

HIGH

7.5

CVSS v3

NVD

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.

CWE-789 CWE-770

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.40%probability of exploitation in 30 days

31stpercentile

Low risk: more likely to be exploited than 31% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-25.