CVE-2026-25899

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 67% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

February 24, 2026

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Aug 2, 2026
Patch available. Sources: github_release, github.
github Patch Available

Denial of Service via Flash Cookie Unbounded Allocation · Advisory · gofiber/fiber · GitHub

https://github.com/gofiber/fiber/security/advisories/GHSA-2mr3-m5q5-wgp6
github_release Patch Available

v3.1.0

Patch available: gofiber/fiber v3.1.0

https://github.com/gofiber/fiber/releases/tag/v3.1.0

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/gofiber/fiber/v3—3.1.0—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-16 14:07 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-13 16:47 UTCEPSS rescore
  5. 2026-09-12 15:01 UTCEPSS rescore
  6. 2026-09-11 14:52 UTCEPSS rescore
  7. 2026-09-10 09:34 UTCEPSS rescore
  8. 2026-09-08 22:00 UTCEPSS rescore
  9. 2026-09-07 16:01 UTCEPSS rescore
  10. 2026-09-06 13:47 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-04 05:06 UTCEPSS rescore
  13. 2026-09-02 14:11 UTCEPSS rescore
  14. 2026-09-01 13:53 UTCEPSS rescore
  15. 2026-09-01 04:39 UTCEPSS rescore
  16. 2026-08-31 16:34 UTCOSV refresh
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:48 UTCEPSS rescore
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 30 more
  1. 2026-08-19 17:03 UTCEPSS rescore
  2. 2026-08-18 13:48 UTCEPSS rescore
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-16 14:56 UTCEPSS rescore
  5. 2026-08-16 02:14 UTCEPSS rescore
  6. 2026-08-15 01:30 UTCEPSS rescore
  7. 2026-08-14 09:05 UTCEG score recompute
  8. 2026-08-13 22:00 UTCEPSS rescore
  9. 2026-08-13 01:04 UTCEG score recompute
  10. 2026-08-12 13:50 UTCEPSS rescore
  11. 2026-08-12 00:49 UTCEG score recompute
  12. 2026-08-11 13:42 UTCEPSS rescore
  13. 2026-08-11 06:29 UTCEG score recompute
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-09 20:33 UTCEG score recompute
  16. 2026-08-09 13:46 UTCEPSS rescore
  17. 2026-08-09 08:42 UTCEG score recompute
  18. 2026-08-08 16:37 UTCEPSS rescore
  19. 2026-08-07 20:48 UTCEG score recompute
  20. 2026-08-06 13:46 UTCEPSS rescore
  21. 2026-08-06 03:03 UTCEG score recompute
  22. 2026-08-05 19:17 UTCEPSS rescore
  23. 2026-08-04 15:10 UTCEPSS rescore
  24. 2026-08-02 19:39 UTCEG score recompute
  25. 2026-08-02 02:26 UTCEPSS rescore
  26. 2026-08-01 04:16 UTCEPSS rescore
  27. 2026-07-30 16:27 UTCEPSS rescore
  28. 2026-07-30 01:30 UTCEPSS rescore
  29. 2026-07-28 15:36 UTCEPSS rescore
  30. 2026-07-27 14:07 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-25899?
CVE-2026-25899 is a high vulnerability published on February 24, 2026. 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…
When was CVE-2026-25899 disclosed?
CVE-2026-25899 was first published in the National Vulnerability Database on February 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-25899 actively exploited?
CVE-2026-25899 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.4% of all scored CVEs.
What is the CVSS score of CVE-2026-25899?
CVE-2026-25899 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-25899?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-25899, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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