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GO-2026-4982

Bypass of meta content URL escaping causes XSS in html/template

Quick fix

GO-2026-4982 — stdlib: upgrade to the fixed version with the command below.

go get stdlib@v1.25.10

Details

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to similarly escape it, leading to XSS.

Are you affected?

Enter the version of the package you're using.

Affected packages

Go / stdlib

Introduced in: 0 Fixed in: 1.25.10

Fix go get stdlib@v1.25.10

References

https://go.dev/issue/78913 [REPORT]
https://go.dev/cl/769920 [FIX]
https://groups.google.com/g/golang-announce/c/qcCIEXso47M [WEB]