# CVE-2026-107381: svg-sanitizer case-insensitive xlink:href DoS bypass

Source: https://junglewise.ai/threats/cve-2026-107381-svg-sanitizer-mixed-case-xlink-href-skips-the-use-nesting-dos  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-14. Updated: 2026-10-08  
License: CC BY 4.0 with a link back

CVE-2026-107381 · Severity: medium · CVSS 6.5 · Published 2026-10-14

The svg-sanitizer library fails to block maliciously nested SVG `<use>` elements when they use mixed-case attribute names like `xlink:HrEf`. An attacker can upload an SVG with this bypassed nesting structure, and the library will output it unchanged with canonical casing, potentially causing a denial-of-service through recursive element expansion in downstream renderers.

Technologies: [Enshrined Svg-Sanitizer](https://junglewise.ai/threats/technologies/svg-sanitizer), [enshrined/svg-sanitize (Packagist)](https://junglewise.ai/threats/technologies/enshrined-svg-sanitize). Vendors: [Enshrined](https://junglewise.ai/threats/vendors/enshrined), [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-107381 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-107381 being exploited in the wild.

**How severe is CVE-2026-107381?** Medium severity, with a CVSS score of 6.5, published 14 October 2026.

**Which products and versions are affected?** Enshrined Svg-Sanitizer 0.22.0 and earlier; enshrined/svg-sanitize (Packagist) <= 0.22.0, ECOSYSTEM:introduced=0,fixed=1.0.0.

**Is there a fix for CVE-2026-107381?** Yes. enshrined/svg-sanitize (Packagist): upgrade to 1.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-107381 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-107381?** Check whether you run Enshrined Svg-Sanitizer or enshrined/svg-sanitize (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- enshrined/svg-sanitize (Packagist): upgrade to 1.0.0 or later

  ```sh
  composer require enshrined/svg-sanitize:^1.0.0
  ```


## Technical details

The vulnerability is a case-sensitivity mismatch: `Resolver::processReferences()` uses XPath with case-sensitive attribute selection `[@href or @xlink:href]`, but `Sanitizer::cleanHrefAttributes()` later normalizes mixed-case attribute names to lowercase. An attacker can bypass the nesting-DoS protection by submitting SVG with `xlink:HrEf` (mixed case), which is not caught by the reference graph but then normalized to `xlink:href` in the output, creating a live nesting bomb that should have been stripped. The fix requires either case-insensitive attribute matching in the XPath query or reordering the sanitizer pipeline so attribute normalization occurs before graph collection.

## Affected products

- enshrined svg-sanitizer 0.22.0 and earlier

## Identifiers

- CVE-2026-107381
- GHSA-m9xh-6747-9r6f

## Timeline

- 2026-10-08: disclosed

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