CVE-2026-42554
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.
How to fix
- gofiber fiber2.52.12, 3.1.0 or later
- github.com/gofiber/fiber/v33.2.0 or later
- github.com/gofiber/fiber/v22.52.13 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| gofiber fiber | v < 2.52.12, 3.0.0 ≤ v < 3.1.0 | 2.52.12, 3.1.0 |
| github.com/gofiber/fiber/v3Go | v < 3.2.0 | 3.2.0 |
| github.com/gofiber/fiber/v2Go | v < 2.52.13 | 2.52.13 |
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Attack Surface Management
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