// For flags

CVE-2026-39823

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

Severity Score

6.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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.

*Credits: Samy Ghannad
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2026-04-07 CVE Reserved
  • 2026-05-07 CVE Published
  • 2026-05-13 CVE Updated
  • 2026-05-14 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Golang
Search vendor "Golang"
 Go
Search vendor "Golang" for product "Go"
 < 1.25.10
Search vendor "Golang" for product "Go" and version " < 1.25.10"
-
Affected
Golang
Search vendor "Golang"
 Go
Search vendor "Golang" for product "Go"
 >= 1.26.0 < 1.26.3
Search vendor "Golang" for product "Go" and version " >= 1.26.0 < 1.26.3"
-
Affected