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Description

A flaw was found in Yelp due to an overly permissive Content Security Policy (CSP) implementation provided by yelp-xsl. A malicious Flatpak application can open crafted help content through the OpenURI portal. By embedding an untrusted CSS stylesheet within a structured SVG document, attacker-controlled content can bypass Flatpak's intended sandbox isolation, allowing Yelp to evaluate local XML inclusions and disclose arbitrary user-readable host files through remote CSS resource requests. This may result in the unauthorized disclosure of sensitive information.

PUBLISHED Reserved 2026-06-29 | Published 2026-06-29 | Updated 2026-07-08 | Assigner redhat




HIGH: 7.1CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Problem types

Protection Mechanism Failure

Product status

Default status
unknown

Default status
affected

Default status
affected

Default status
affected

Timeline

2026-06-29:Reported to Red Hat.
2026-05-07:Made public.

Credits

Red Hat would like to thank Codean Labs for reporting this issue.

References

access.redhat.com/security/cve/CVE-2026-13601 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2494110 (RHBZ#2494110) issue-tracking

security.access.redhat.com/...2/vex/2026/cve-2026-13601.json

access.redhat.com/security/cve/CVE-2026-13601 vdb-entry

blogs.gnome.org/...26/05/11/flatpak-sandbox-escape-via-yelp/

bugzilla.redhat.com/show_bug.cgi?id=2494110 (RHBZ#2494110) issue-tracking

gitlab.gnome.org/...c8c8244c8a812860782d635890c9b6c43ecc2639

gitlab.gnome.org/GNOME/yelp/-/work_items/238

cve.org (CVE-2026-13601)

nvd.nist.gov (CVE-2026-13601)

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