CVE-2026-27136: golang.org/x/net/html · Cross-site Scripting
Affects golang.org/x/net/htmlSource CVE Database V5
Not known to be exploited · CVSS 6.1 Medium : upgrade to 0.55.0 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.55.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade golang.org/x/net/html to 0.55.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| golang.org/x/netgolang.org/x/net/html | Affected
| Fixed in
|
Gogolang.org/x/net/htmlpkg:golang/golang.org/x/net/htmlOther threats | Affected
| Fixed in– |
Gogolang.org/x/net/htmlpkg:golang/golang.org/x/net/htmlOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, users should exercise caution when using golang.org/x/net/html to sanitize untrusted HTML input and consider additional layers of input validation or sanitization outside this package.
Description
CVE-2026-27136 is a medium severity vulnerability in the golang.org/x/net/html package where parsing arbitrary HTML and rendering it using the Render function can produce an unexpected HTML tree. This behavior may be exploited to perform cross-site scripting (XSS) attacks in applications that rely on this package to sanitize input HTML before rendering. The vulnerability involves improper neutralization of input during web page generation (CWE-79).