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VulnerabilityPublished

CVE-2026-44332: V3 · GoFiber Vulnerable to Username Enumeration via Timing Oracle in BasicAuth Default Authorizer

Affects github.com/gofiber/fiber/v3Source GCVE Database

0

Not known to be exploited · CVSS 5.3 Medium : upgrade to 3.3.0 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Affects
Go. prior to 3.3.0
Patch
Available – fixed in 3.3.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade github.com/gofiber/fiber/v3 to 3.3.0.

Affected software

ProductAffectedFixed in
Gogithub.com/gofiber/fiber/v3Affected
  • <3.3.0
Fixed in
  • 3.3.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, consider implementing custom Authorizer logic that performs consistent-time password hash verification regardless of username validity to mitigate timing discrepancies.

Description

Fiber is an Express inspired web framework written in Go. Prior to 3.3.0, the default Authorizer function in the BasicAuth middleware in middleware/basicauth/config.go uses short-circuit evaluation that skips password hash comparison for non-existent usernames, enabling reliable remote username enumeration through response timing differences. This issue is fixed in version 3.3.0.

References

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