CVE-2026-42554

6.1 MEDIUM
Published: May 11, 2026 Modified: May 18, 2026
View on NVD

Description

Fiber is a web framework for Go. Prior to 2.52.12 and 3.1.0, Cross-Site Scripting vulnerability in Go Fiber allows a remote attacker to inject arbitrary HTML/JavaScript by supplying Accept: text/html on any request whose handler passes attacker-influenced data to the AutoFormat() feature. The developer opts into content negotiation by calling AutoFormat(), but does not opt into raw HTML emission for a particular request; Fiber chooses that branch from attacker-controlled Accept. The html branch is the sole outlier in a method whose name (AutoFormat) and symmetrical structure actively telegraph "safe, format-agnostic reply." This vulnerability is fixed in 2.52.12 and 3.1.0.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjv
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory
https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjv
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Mitigation Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.1 / 10.0
EPSS (Exploit Probability)
0.2%
11th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

gofiber