What’s Vulnerable › Vulnerabilities

CVE-2023-24539: Improper sanitization of CSS values in html/template

• Severity: high (CVSS 7.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-05-11 · updated 2026-06-17
• Weakness: CWE-74

Description

Angle brackets (<>) are not considered dangerous characters when inserted into CSS contexts. Templates containing multiple actions separated by a '/' character can result in unexpectedly closing the CSS context and allowing for injection of unexpected HTML, if executed with untrusted input.

Affected products

• Go: before 1.19.9; from 1.20.0 before 1.20.4 — fixed in 1.19.9, 1.20.4

How to fix

Upgrade to a fixed version: Go 1.19.9, 1.20.4. Check the vendor advisory for mitigations.

References

• https://go.dev/cl/491615
• https://go.dev/issue/59720
• https://groups.google.com/g/golang-announce/c/MEb0UyuSMsU
• https://pkg.go.dev/vuln/GO-2023-1751
• https://go.dev/cl/491615
• https://go.dev/issue/59720
• https://groups.google.com/g/golang-announce/c/MEb0UyuSMsU
• https://pkg.go.dev/vuln/GO-2023-1751
• https://security.netapp.com/advisory/ntap-20241129-0005/

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