vulnerability / NVI-00016385 / Revision 1
ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `` solidus close
GitHub lists this reviewed advisory for sanitize-html. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.1 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
sanitize-html
source listed<= 2.17.5
### Summary A mutation-XSS / allowedTags bypass: when `textarea` (or `xmp`) is included in `allowedTags`, an input containing a literal `` (a solidus right after the RCDATA end-tag name) lets non-allowed markup such as `` pass through `sanitizeHtml()` **live and unescaped**, even though `img`/`onerror` are not in the allowlist. A spec-compliant browser executes the surviving handler — XSS. This is a literal-solidus variant that bypasses the two most recent fixes in this code area (CVE-2026-40186, CVE-2026-44990), both already applied in 2.17.5. The default configuration is not affected. ### Details `sanitize-html` emits the text content of HTML raw-text elements (`textarea`, `xmp`) without escaping. Two things combine: - **Parser differential:** on input, htmlparser2 does NOT recognize `` (solidus after the RCDATA end-tag name) as a close tag; it emits `` as a single raw-text node. - **Unescaped passthrough:** the `ontext` handler (`index.js` ~575-583) appends `textarea`/`xmp` content with `result += text` (no `escapeHtml`), assuming it is "already properly encoded" — true for entity-decoded content (what CVE-2026
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-jxwj-j7wr-gfrw ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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