Skip to main content

Yelp CVE-2026-13601

| EUVDEUVD-2026-40066 MEDIUM
Protection Mechanism Failure (CWE-693)
2026-06-29 secalert@redhat.com GHSA-f4vh-qr53-q5gv
Information Disclosure Red Hat Enterprise Linux Yelp Gnome
6.5
CVSS 3.1 · NVD
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Install/run malicious Flatpak app
  2. Delivery
    Invoke OpenURI portal to Yelp
  3. Exploit
    Deliver crafted SVG with untrusted CSS
  4. Execution
    Yelp evaluates local XML inclusions outside sandbox
  5. Persist
    Read user-readable host files
  6. Impact
    Exfiltrate via remote CSS requests

Vulnerability Assessment

Weakness
CWE
CWE-693
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Protection mechanism completeness
Exploitation Conditions

A malicious or compromised Flatpak application must already be installed and running on the host, and it must be able to invoke the OpenURI portal to hand crafted help content to Yelp. The malicious payload specifically requires an SVG-structured document that embeds an untrusted CSS stylesheet plus local XML inclusions, which Yelp evaluates because of the overly permissive yelp-xsl CSP. Limiting factors: the attack vector is local (AV:L), not network-reachable, so the attacker needs prior local code execution via a sandboxed app the user chose to run; impact is confined to disclosure of files readable by the invoking user (C:H, but I:N/A:N - no write or code execution), and it depends on a system using Yelp with the vulnerable yelp-xsl CSP and on OpenURI being available to the malicious app. The CVSS PR:N/UI:N reflects that no host privileges or extra user clicks are needed once the malicious app runs.
Impact

The CVSS 3.1 base score is 7.1 (AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N): local attack vector, low complexity, no privileges, no user interaction, a changed scope (sandbox-to-host escape), and high confidentiality impact with no integrity or availability impact - consistent with a read-only information-disclosure sandbox escape rather than code execution. The 'local' vector is the key limiter: exploitation is not remote/network-reachable but requires the attacker's code to already be running locally as a Flatpak application (e.g., a malicious or trojanized app the user installed), which the PR:N reflects since a sandboxed app legitimately holds no special host privileges. No EPSS score was provided in the input, the CVE is not in CISA KEV, and no POC/exploit code is referenced, so this is a credible but not actively-exploited issue. SSVC-style read: exploitation is 'none observed,' technical impact is partial (confidentiality only), and automatability is plausible once a malicious app is delivered. Net priority is moderate - meaningful for multi-tenant or untrusted-app desktop scenarios (the entire point of Flatpak sandboxing), but it does not enable remote compromise on its own and depends on the user running attacker-controlled Flatpak software.
Exploit ScenarioDerived

A user installs a seemingly benign Flatpak application; while running inside its sandbox, the app calls the OpenURI portal to open crafted help content in Yelp containing an SVG that wraps a malicious CSS stylesheet and local XML inclusions. Yelp, running outside the sandbox, evaluates the attacker content under the permissive yelp-xsl CSP, reads user-readable host files, and leaks their contents through remote CSS resource requests to an attacker server. No public POC is referenced, but the GNOME blog post describes the technique; the local, low-complexity, no-interaction profile (AV:L/AC:L/UI:N) makes it straightforward once a malicious app is present.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Jun 29, 2026

Sandbox-escaping information disclosure in Yelp (the GNOME help viewer) lets a malicious Flatpak application read arbitrary user-readable files on the host. By using the OpenURI portal to open crafted help content that embeds an untrusted CSS stylesheet inside a structured SVG document, an attacker abuses an overly permissive Content Security Policy supplied by yelp-xsl to force Yelp to evaluate local XML inclusions and exfiltrate file contents via remote CSS resource requests, defeating Flatpak's intended isolation. The flaw was disclosed publicly (GNOME developer blog by Michael Catanzaro, May 2026) and tracked by Red Hat; no public exploit identified at time of analysis and it is not listed in CISA KEV.

RemediationAI

Upstream fix available (PR/commit); released patched version not independently confirmed - apply the distribution package update that incorporates GNOME GitLab commit c8c8244c8a812860782d635890c9b6c43ecc2639 for Yelp (and the corresponding yelp-xsl CSP tightening), tracking your distro's advisory via the Red Hat entry at https://access.redhat.com/security/cve/CVE-2026-13601 and Bugzilla 2494110 (https://bugzilla.redhat.com/show_bug.cgi?id=2494110) for the exact patched build for your OS. Until the package is updated, reduce exposure by only installing Flatpak applications from trusted sources and review/limit which apps are allowed to use the OpenURI portal - restricting or denying OpenURI access for untrusted apps (e.g., via portal/permission configuration) prevents the delivery path, at the cost of breaking legitimate 'open in help/browser' behavior for those apps. Avoid setting Yelp as the handler for content originating from untrusted sandboxed applications; the side effect is that in-app help links from those apps will no longer open automatically. Consult the technical analysis at https://blogs.gnome.org/mcatanzaro/2026/05/11/flatpak-sandbox-escape-via-yelp/ for details before relying on workarounds.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Sign in to check
Technical ContextAI · show details

The root cause is classified as CWE-693 (Protection Mechanism Failure): the CSP that yelp-xsl ships for rendered help documents is too permissive, so Yelp's WebKit-based rendering pipeline does not block externally-controlled resource loads or local XML entity/inclusion processing that a hardened policy would prevent. The attack composes several desktop technologies - Flatpak's portal system (specifically the OpenURI portal, the sanctioned cross-sandbox mechanism for asking the host to open a URI), Yelp's Mallard/DocBook XML help rendering, and SVG/CSS processing. An SVG document is used as a structured carrier so that an embedded CSS stylesheet and local XML inclusions are evaluated in Yelp's (host-side, unsandboxed) context; the contents of user-readable host files are then leaked outbound through remote CSS resource fetches (a classic CSS/XML-inclusion side channel). Because Yelp runs outside the calling app's Flatpak sandbox, evaluating attacker-controlled content there constitutes a confidentiality scope change from the sandbox to the host.

Know when Yelp gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources
Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 6.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
vuln.today AI 7.1 HIGH

Requires a locally-running sandboxed app (AV:L) but no host privileges or interaction (PR:N/UI:N); sandbox-to-host escape changes scope (S:C) and leaks files (C:H) without integrity/availability impact.

3.1 AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
4.0 AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
SUSE 7.1 HIGH
AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Red Hat 7.1 HIGH

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

2
Severity Changed
Jul 08, 2026 - 03:37 NVD
HIGH MEDIUM
CVSS changed
Jul 08, 2026 - 03:37 NVD
7.1 (HIGH) 6.5 (MEDIUM)

DescriptionNVD

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.

Executive ViewAI

Why It Matters

A high-severity information disclosure flaw in Yelp (GNOME's help viewer) allows malicious Flatpak applications to bypass container sandboxing and access arbitrary user files. This vulnerability directly undermines the isolation model that container-based application deployment relies on, creating data exposure risk across systems using containerized applications.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Disable Flatpak on systems where containerized application support is not required; (2) restrict Flatpak application installations to vetted, trusted packages only; (3) remove or quarantine untrusted containerized applications; (4) deploy network controls to monitor and block unusual CSS resource requests from help viewer processes; (5) enable enhanced logging and auditing of file access patterns and help viewer activity to detect exploitation.

Threat Intelligence Overview

EPSS Score
0.1%
Top 96% exploitable
Prevalence
High
default help viewer on most GNOME-based Linux desktop installations
Social Media
3
Sightings
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor CIRCL VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:gnome:yelp:*:*:*:*:*:*:*:*

More in Yelp

View all
CVE-2018-10406 HIGH POC
7.8 Jun 13

An issue was discovered in Yelp OSXCollector. Rated high severity (CVSS 7.8), this vulnerability is no authentication re
CVE-2025-3155 HIGH POC
7.4 Apr 03

A flaw was found in Yelp. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication

Same weakness CWE-693 – Protection Mechanism Failure

View all
CVE-2013-2465 CRITICAL POC
9.8
CVE-2024-21412 HIGH POC
8.1
CVE-2019-1003030 CRITICAL POC
9.9
CVE-2013-0431 LOW POC
3.7
CVE-2025-40536 HIGH POC
8.1
CVE-2024-38217 MEDIUM POC
5.4
CVE-2026-21513 HIGH
8.8
CVE-2026-21510 HIGH POC
8.8

Same technique Information Disclosure

View all
CVE-2019-2725 CRITICAL POC
9.8
CVE-2021-34523 CRITICAL POC
9.0
CVE-2013-2251 CRITICAL POC
9.8
CVE-2017-5638 CRITICAL POC
9.8
CVE-2025-24813 CRITICAL POC
9.8
CVE-2025-68613 HIGH POC
8.8
CVE-2015-1701 HIGH POC
7.8
CVE-2017-0147 HIGH POC
7.5

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS Affected
SUSE Linux Enterprise Module for Desktop Applications 15 SP7 Affected

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-13601 ADVISORY https://vuldb.com/vuln/374605 REF https://access.redhat.com/errata/RHSA-2026:47177 REF https://access.redhat.com/errata/RHSA-2026:47178 REF https://access.redhat.com/errata/RHSA-2026:54539 REF https://access.redhat.com/errata/RHSA-2026:54540 REF https://access.redhat.com/errata/RHSA-2026:54605 REF https://access.redhat.com/errata/RHSA-2026:54624 REF https://access.redhat.com/errata/RHSA-2026:54637 REF https://access.redhat.com/errata/RHSA-2026:54666 REF https://access.redhat.com/errata/RHSA-2026:57417 REF https://access.redhat.com/security/cve/CVE-2026-13601 REF https://blogs.gnome.org/mcatanzaro/2026/05/11/flatpak-sandbox-escape-via-yelp/ REF https://bugzilla.redhat.com/show_bug.cgi?id=2494110 REF https://gitlab.gnome.org/GNOME/yelp/-/commit/c8c8244c8a812860782d635890c9b6c43ecc2639 REF https://gitlab.gnome.org/GNOME/yelp/-/work_items/238 REF https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-13601.json

Search Externally

GitHub PoC Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy