CVE-2026-44332

Fiber: Username Enumeration via Timing Oracle in BasicAuth Default Authorizer

MEDIUM
5.3
CVSS Score
Published: July 8, 2026 at 07:32 PM UTC
Updated: October 25, 2026 at 05:10 PM UTC
1 product affected across 1 vendorFiber

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.3.0
Affected range stops below 3.3.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/gofiber/fiber/security/advisories/GHSA-g5vh-55hw-rxm8
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/gofiber/fiber/pull/4245
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/gofiber/fiber/releases/tag/v3.3.0

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-203

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