What is the CVSS score of CVE-2025-6558?

CVE-2025-6558 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Is CVE-2025-6558 being actively exploited?

Yes, CVE-2025-6558 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

How to fix or mitigate CVE-2025-6558?

Within 24 hours, confirm exposure by inventorying Chrome, Chromium-based browsers, Safari/WebKit, webkitgtk, wpewebkit, and Qt WebEngine on Alpine Linux (versions before 6.9.1-r3), and push any available vendor updates or hotfixes from Google, Apple, and other maintainers while treating the ANGLE/WebKit flaw as actively exploited. Within 7 days, apply compensating controls on unpatched systems: enforce strict site isolation, enable browser sandboxing, block known malicious domains and untrusted HTML content at the web gateway, restrict or disable unnecessary browser extensions and plug-ins, and require users to avoid untrusted links and attachments. Within 30 days, establish a recurring patch-validation process for all browser and WebKit components, deploy endpoint detection and response coverage for browser exploitation behavior, perform a threat hunt for indicators tied to this CVE, and re-evaluate risk once vendor patches become available.

Google Chrome CVE-2025-6558

HIGH

Improper Input Validation (CWE-20)

N/A vendor:alpine

Information Disclosure Google Apple Debian Debian Linux Ipados Iphone Os Visionos Watchos Webkitgtk Wpe Webkit Chromium Wpewebkit

8.8

CVSS 3.1 · Vendor: vendor:alpine

View

Attack ChainAIDerived

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

Access

Host crafted HTML page
Delivery

Lure victim to visit (UI:R)
Exploit

Feed malformed input to ANGLE/GPU
Execution

Trigger sandbox escape
Persist

Execute code outside renderer
Impact

Full host compromise

Vulnerability Assessment

Weakness	CWE CWE-20 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions	Exploitation requires the victim to load attacker-controlled web content in a vulnerable Chromium- or WebKit-based browser/engine (Google Chrome pre-fix, Apple Safari/WebKit, webkitgtk, wpewebkit, or Qt WebEngine before 6.9.1-r3 on Alpine). The only limiting factor is user interaction (UI:R) - the victim must visit or render a crafted HTML page (which can be delivered via malicious site, iframe, or ad); no authentication, no privileges, and no non-default configuration are needed. The malformed input targets the ANGLE/GPU processing path, so environments that disable GPU/hardware acceleration or heavily sandbox rendering may raise the bar, but default browser configurations are exploitable.
Impact	This is a genuine high-priority vulnerability despite the deceptively narrow Alpine description ('qt6-qtwebengine fixed in 6.9.1-r3'). The CPE list and references make clear this is CVE-2025-6558 - insufficient validation of untrusted input in Chromium's ANGLE/GPU components enabling a sandbox escape - which propagates into every downstream consumer of the engine (Google Chrome, Apple Safari/WebKit, webkitgtk, wpewebkit, Qt WebEngine, Debian). CISA KEV = YES, meaning confirmed active exploitation in the wild, which is the single strongest prioritization signal and overrides the otherwise-modest EPSS score of 0.25% (49th percentile). The low EPSS despite KEV listing is not contradictory: EPSS models broad, automated exploitation likelihood, whereas KEV reflects observed targeted use - a browser sandbox escape is typically chained and used against selected targets rather than sprayed, so 'low EPSS + KEV' here signals targeted rather than mass exploitation. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, 8.8) is consistent with a drive-by web attack requiring only that a victim visit a crafted page (UI:R). The 'Information Disclosure' tag understates the true impact, which is full C/I/A compromise via sandbox escape. Bottom line: patch immediately - this is a confirmed-exploited, network-reachable, no-privilege browser bug in ubiquitous software.
Exploit ScenarioDerived	An attacker hosts a malicious web page (or injects a malicious iframe/ad) that delivers crafted input to the ANGLE/GPU layer of a Chromium/WebKit-based browser. When a victim merely visits the page, the flaw triggers a renderer sandbox escape, giving the attacker code execution outside the browser's security boundary. This vulnerability is listed in CISA KEV as actively exploited in the wild, indicating working exploit capability already exists.

Act Now Prioritize within 24-48h. Why: Active threat signals + CRITICAL/HIGH severity.

Exploited in the wild (CISA KEV) No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv2 – Sep 24, 2026

Remote code execution in Google Chrome's ANGLE graphics layer allows attackers to compromise systems via crafted HTML pages; the same flaw affects other Chromium- and WebKit-based browsers, including Apple Safari/WebKit, webkitgtk, wpewebkit, and Qt WebEngine before 6.9.1-r3 on Alpine Linux. Exploitation requires only user interaction (victim views malicious web content) and no authentication; it has been confirmed actively exploited (CISA KEV), though EPSS probability is currently low (0.25%, 49th percentile).

Earlier versions of this analysis (1)

v1 May 27, 2026 - 22:34

Active exploitation confirmed by CISA KEV affects qt6-qtwebengine on Alpine Linux, with the vulnerability addressed in package version 6.9.1-r3. The specific vulnerability class and technical mechanism are not disclosed in available intelligence - the only confirmed data point beyond KEV status is the Alpine Linux package fix designation. Despite CISA KEV confirmation, the EPSS score of 0.25% (49th percentile) is notably low, indicating exploitation is targeted rather than widespread or automated. Any application or system running Alpine Linux with qt6-qtwebengine prior to 6.9.1-r3 should be treated as at risk given the confirmed exploitation status.

RemediationAI

Upgrade to patched versions: Google Chrome 138.0.7204.157 or later (see https://chromereleases.googleblog.com/2025/07/stable-channel-update-for-desktop_15.html), Alpine Linux qt6-qtwebengine 6.9.1-r3 or later, and apply the latest security updates for Apple operating systems and Debian Linux 11.0 (see https://lists.debian.org/debian-lts-announce/2025/08/msg00015.html). Given active exploitation per CISA KEV, prioritize patching. If immediate upgrade is not possible, disabling WebGL or hardware acceleration in browsers may reduce the attack surface but impacts performance and may not fully mitigate; also keep browser sandboxing enabled and avoid rendering untrusted content. Consult the CISA KEV catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-6558 for updates.

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Technical ContextAI · show details

The vulnerability resides in ANGLE (Almost Native Graphics Layer Engine), a cross-platform graphics translation layer used by Chromium and WebKit to translate OpenGL ES calls to platform-specific APIs. The flaw stems from improper input validation (CWE-20) in the GPU processing path, where malformed HTML content can cause memory corruption. According to CPE data and vendor advisories, the issue affects Google Chrome, Apple Safari, iOS, iPadOS, macOS, visionOS, watchOS, Debian Linux 11.0, webkitgtk, wpewebkit, and Qt WebEngine (bundled in Alpine Linux). The CVSS vector indicates network attack vector, low attack complexity, no privileges required, but user interaction is necessary (UI:R), with high impact on confidentiality, integrity, and availability.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (vendor:alpine) PRIMARY 8.8 HIGH

AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

vuln.today AI 8.8 HIGH

Remote crafted web page needs only a victim visit (UI:R) with no privileges; sandbox escape yields full code execution, hence C:H/I:H/A:H.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (vendor:alpine).

CVSS VectorVendor: vendor:alpine

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVSS changed

Sep 24, 2026 - 13:22 NVD

8.8 (HIGH)

CVE Published

May 27, 2026 - 22:34 nvd

MEDIUM

Added to CISA KEV

May 27, 2026 - 22:03 CISA

DescriptionCVE.org

Alpine Linux: qt6-qtwebengine fixed in 6.9.1-r3

Executive ViewAI

Why It Matters

A high-severity remote code execution vulnerability in Google Chrome's ANGLE graphics layer is confirmed actively exploited (CISA KEV) and also affects other Chromium- and WebKit-based browsers, including Apple Safari/WebKit, webkitgtk, wpewebkit, and Qt WebEngine on Alpine Linux before 6.9.1-r3. Any employee, contractor, or customer using an affected browser can be compromised simply by viewing a malicious web page, making this an organization-wide endpoint and browser risk. Because no vendor patch is currently available, leadership should expect heightened exposure until mitigations and vendor updates are in place.

Business Impact: High

Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations include enforcing browser site isolation and sandboxing, restricting access to untrusted web content and links, filtering known malicious domains at the network perimeter, disabling unnecessary browser extensions, and monitoring endpoints for exploitation indicators.

Threat Intelligence Overview

EPSS Score

0.3%

Top 51% exploitable

Prevalence

Ubiquitous

Chromium/WebKit engine ships in Chrome, Safari, and countless embedded browsers

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

CISA KEV

EPSS

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 HIGH

CISA KEV Yes

Public POC No

EPSS 0.3%

Patch available No

Active threat Yes

Deciding rule

Active threat signals + CRITICAL/HIGH severity

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· derived

Out-of-Cycle

Exploitation· derived

Active

System Exposure· derived

Open

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: +50

EPSS: 0

CVSS: +44

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.