svg-sanitizer: Mixed-case xlink:HrEf skips the nesting-DoS check in Resolver::processReferences

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-107381: 0.47% estimated exploitation activity in the next 30 days; percentile 40.56 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Resolver::processReferences() collects <use elements with the XPath predicate use[@href or @xlink:href], which is case sensitive. A <use element written as xlink:HrEf is therefore never added to the reference graph, so the nesting-DoS nullification never marks it for removal. Sanitizer::cleanHrefAttributes() then runs later in the same pass and rewrites xlink:HrEf back to the canonical xlink:href. The sanitizer hands back a fully live nesting bomb that it would have stripped completely had the input used canonical casing. This is the mirror image of CVE-2025-55166: that fix made href value checking case insensitive, but the <use reference graph still selects nodes case sensitively. Where it is src/ElementReference/Resolver.php:97-118, the case-sensitive node selection: src/Sanitizer.php:479-504, the normalization that happens afterwards and makes the attribute live again: Ordering is the whole bug. Sanitizer::sanitize() builds the resolver graph first and normalizes attribute…

Published by the source

8 Oct 2026, 19:41 UTC

Last modified by the source

8 Oct 2026, 20:00 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m9xh-6747-9r6f

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-m9xh-6747-9r6f

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# Patch Next advisory brief: CVE-2026-107381

Advisory: svg-sanitizer: Mixed-case xlink:HrEf skips the ` ` nesting-DoS check in Resolver::processReferences
IDs: CVE-2026-107381, GHSA-m9xh-6747-9r6f
Record: https://patchnext.com/advisories/cve-2026-107381 (revision 2, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: enshrined/svg-sanitize 1.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist enshrined/svg-sanitize: affected <= 0.22.0; fixed in 1.0.0

## Suggested inspection (read-only)
- Packagist enshrined/svg-sanitize: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on enshrined/svg-sanitize.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m9xh-6747-9r6f (OSV record GHSA-m9xh-6747-9r6f lists affected ranges: Packagist enshrined/svg-sanitize >=0 <1.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-m9xh-6747-9r6f (GitHub-reviewed advisory GHSA-m9xh-6747-9r6f lists affected ranges: Packagist enshrined/svg-sanitize >=0 <=0.22.0)

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