CVE-2026-27142 URLs in meta content attribute actions are not escaped in html/template
Attackers can execute arbitrary JavaScript via unescaped URLs in meta content attributes when http-equiv refresh is used.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-27142?
CVE-2026-27142 is a medium-severity cross-site scripting vulnerability in Golang Go, published on 6 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Actions which insert URLs into the content attribute of HTML meta tags are not escaped. This can allow XSS if the meta tag also has an http-equiv attribute with the value "refresh". A new GODEBUG setting has been added, htmlmetacontenturlescape, which can be used to disable escaping URLs in actions in the meta content attribute which follow "url=" by setting htmlmetacontenturlescape=0.
Weakness: CWE-79
Which versions are affected by CVE-2026-27142?
2 open source packages ship an affected version, including golang and stdlib. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
golang Bitnami | All versions | 1.25.8, 1.26.1 |
stdlib Go | All versions | 1.25.8, 1.26.1 |
Linux distribution packages (7)
golang1.25 Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-bin Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-docs Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-misc Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-shared Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-src Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
golang1.25-tests Red Hat:hummingbird:1 | All versions | 0:1.25.8-1.1.hum1 |
Products include Golang Go.
How do I fix CVE-2026-27142?
Upgrade golang to a fixed version for your release line: 1.25.8 or 1.26.1.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-27142 being exploited?
There is no known exploitation of CVE-2026-27142 in the wild and no public exploit code.
Other vulnerabilities in Golang Go
- CVE-2020-0601 Microsoft Windows CryptoAPI Spoofing
- CVE-2026-27143 Missing bound checks can lead to memory corruption in safe Go in cmd/compile
- CVE-2024-24790 Unexpected behavior from Is methods for IPv4-mapped IPv6 addresses in net/netip
- CVE-2023-39320 Arbitrary code execution via go.mod toolchain directive in cmd/go
- CVE-2023-24540 Improper handling of JavaScript whitespace in html/template
Sources
Also known as AZL-79601, AZL-79604, AZL-79607, AZL-79616, AZL-79619, AZL-79622 and 545 more.