Fiber: Username Enumeration via Timing Oracle in BasicAuth Default Authorizer

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Summary

CVECVE-2026-44332
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-08 20:16:49 UTC
Updated2026-07-10 19:01:16 UTC
DescriptionFiber 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

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

EPSS: 0.005160000 probability, percentile 0.402580000 (date 2026-07-12)

Problem Types: CWE-203 | CWE-203 CWE-203: Observable Discrepancy

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Gofiber Fiber affected < 3.3.0 Not specified

References

ReferenceSourceLinkTags
github.com/gofiber/fiber/releases/tag/v3.3.0 [email protected] github.com
github.com/gofiber/fiber/pull/4245 [email protected] github.com
github.com/gofiber/fiber/commit/c7ac00edd19f9669b1aebbec6e229658baaa059e [email protected] github.com
github.com/gofiber/fiber/security/advisories/GHSA-g5vh-55hw-rxm8 [email protected] github.com
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