CVE-2026-25899Public exploitNetwork attack vector

Unauthenticated server crash via flash cookie allocation

Published Feb 24, 2026 · Updated Feb 24, 2026

Denial of service in GoFiber Fiber 3.0.0 allows remote attackers to crash servers via a crafted fiber_flash cookie. parseAndClearFlashMessages hex-decodes the cookie, and UnmarshalMsg passes its attacker-controlled array32 count to an unbounded redirectionMsgs allocation. No authentication or flash-message use is required; any endpoint can attempt an allocation of up to 85 GB and exhaust the server process.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in GoFiber Fiber 3.0.0 allows remote attackers to crash servers via a crafted fiber_flash cookie. parseAndClearFlashMessages hex-decodes the cookie, and UnmarshalMsg passes its attacker-controlled array32 count to an unbounded redirectionMsgs allocation. No authentication or flash-message use is required; any endpoint can attempt an allocation of up to 85 GB and exhaust the server process.

The record

CVE
CVE-2026-25899
Published
Feb 24, 2026
Updated
Feb 24, 2026
Vendor
GoFiber
Product
Fiber
Classifications
CWE-789, CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.0.0, < 3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GoFiber · Fiberversion=>= 3.0.0, < 3.1.0

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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