CVE-2026-25543 json
HtmlSanitizer has a bypass via template tag
published 2026-02-03 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-5328 , GHSA-j92c-7v7g-gj3f
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 19%
- public exploits
- 0
- none known
Summary
HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta.
Patch / fix
- nuget HtmlSanitizer 9.0.892, 9.1.893-beta
- htmlsanitizer_project htmlsanitizer 9.0.892, 9.1.893-beta
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 9 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N |
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| nuget | HtmlSanitizer | <9.0.892 >=9.1.878-beta, <9.1.893-beta |
9.0.892 9.1.893-beta |
Affected products
- mganss HtmlSanitizer
Classification
References
-
github.com
/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a5066933d82b81
web, patch
-
github.com
/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3f
web, mitigation, patch, vendor-advisory
-
nuget.org
/packages/HtmlSanitizer/9.0.892
web, product, release-notes
-
nuget.org
/packages/HtmlSanitizer/9.1.893-beta
web, product, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-25543
advisory
-
developer.mozilla.org
/en-US/docs/Web/HTML/Reference/Elements/template
web
-
github.com
/mganss/HtmlSanitizer
package
-
github.com
/mganss/HtmlSanitizer/releases/tag/v9.0.892
web
Sources
- CVE List CVE-2026-25543
- GitHub Advisory GHSA-j92c-7v7g-gj3f
- NVD CVE-2026-25543
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.