Snipe-IT vulnerable to stored XSS via inline-served attachment

Exploitation

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

CVSS 4.0

6.2 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N · score source

EPSS

• CVE-2026-55466: 0.44% estimated exploitation activity in the next 30 days; percentile 38.25 (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.

Impact A low-privilege user can store an active-content payload as an asset attachment and have it served inline, same-origin, with an active Content-Type, achieving stored XSS. The application sanitizes uploads only when PHP finfo detects image/svg+xml. By submitting an XHTML document whose finfo MIME is text/xml (an allowed extension), the svg-sanitize branch is skipped, the <script is stored raw, and the inline-serve path returns it as text/xml; charset=utf-8 with Content-Disposition: inline — which the browser renders as a live XHTML document and executes. The dedicated StorageHelper::allowSafeInline() whitelist that should have constrained inline-renderable types is never wired into the serve path. Details Vulnerable code — sanitizer keyed on finfo MIME app/Http/Requests/UploadFileRequest.php:46-53 Vulnerable code — inline serve, no allowSafeInline() app/Http/Controllers/UploadedFilesController.php:103 StorageHelper::allowSafeInline() (app/Helpers/StorageHelper.php:88) exists to…

Published by the source

28 Aug 2026, 17:59 UTC

Last modified by the source

28 Aug 2026, 17:59 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jhph-5q74-pmfx

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# Patch Next advisory brief: CVE-2026-55466

Advisory: Snipe-IT vulnerable to stored XSS via inline-served attachment
IDs: CVE-2026-55466, GHSA-jhph-5q74-pmfx
Record: https://patchnext.com/advisories/cve-2026-55466 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: snipe/snipe-it 8.6.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist snipe/snipe-it: affected <= 8.6.1; fixed in 8.6.2

## Suggested inspection (read-only)
- Packagist snipe/snipe-it: 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 snipe/snipe-it.
- 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://github.com/advisories/GHSA-jhph-5q74-pmfx (GitHub-reviewed advisory GHSA-jhph-5q74-pmfx lists affected ranges: Packagist snipe/snipe-it >=0 <=8.6.1)

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