CVE-2026-42554

MEDIUM EPSS 11.5%
Published May 11, 20261mo ago · Modified Jun 17, 20262w ago
5.3 CVSS 4.0
Medium
Find Similar
Published May 11, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
5.3
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction P
Scope X

Threat Intelligence

EPSS Exploit Probability
11.5% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-79 Cross-site Scripting Injection

Affected Products 2

VendorProductVersionRange
gofiberfiber* <2.52.12
gofiberfiber*≥3.0.0  –  <3.1.0

References 1

  • github.com https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjv
    ExploitMitigationVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.