CVE-2025-13226: High Severity V8 Type Confusion in Chrome Pre 142.0.7444.59

Type confusion in V8 that could be triggered by a crafted HTML page was assigned CVE‑2025‑13226 and affects Google Chrome builds prior to 142.0.7444.59, creating a high‑severity risk of heap corruption that can be weaponized into crashes or, in chained attacks, remote code execution. Security databases and vendor release notes mark this as a network‑accessible vulnerability with low attack complexity and no required privileges, so organizations must treat Chromium runtimes across their estate as potentially exposed until upgrades are verified.

Background / Overview​

V8—the JavaScript and WebAssembly engine embedded in Chromium—operates with aggressive runtime optimizations and typed internal representations. A type confusion flaw occurs when the engine assumes an object has one internal type while it actually has another, violating invariants that the just‑in‑time (JIT) compiler and runtime depend on. In V8, such mismatches can produce memory‑corruption primitives (for example, out‑of‑bounds reads/writes or heap corruption) that attackers escalate into sandbox escapes or native code execution when combined with other primitives. This class of bug is repeatedly treated as urgent by browser vendors because it can be triggered remotely by merely loading a malicious page. Google shipped the Chrome 142 stable channel family (various 142.0.7444.* builds) which contained fixes for multiple V8 issues, and the specific upstream remediation boundary for CVE‑2025‑13226 is Chrome 142.0.7444.59 (and later). Administrators should understand that a Chrome build number is the upstream fix signal; downstream Chromium consumers—Microsoft Edge, Electron apps, embedded WebView runtimes, and appliance vendors—must ingest those changes and ship their own builds before those products are actually remediated. The practical result is a window of residual exposure that can be measured in hours to weeks, depending on vendor release cadences.

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What the vulnerability actually is​

Technical summary​

• Vulnerability class: Type Confusion (CWE‑843) inside V8.
• Affected products: Google Chrome prior to 142.0.7444.59 (and any downstream products embedding the same V8 revision until they ingest the fix).
• Attack vector: Network — a remote attacker can trigger the issue by getting a victim to render a crafted HTML page (for example, via a malicious site, a compromised ad, or weaponized content in an embedded browser).
• Privileges required: None.
• Impact: Heap corruption (stability denial-of-service) at minimum; with exploitation chains, arbitrary code execution is a realistic escalation.
• Public severity: High (CVSS v3.x commonly reported as 8.8 by public trackers).

Why type confusion in V8 is dangerous​

V8 performs numerous optimizations that rely on internal type assumptions: maps, hidden classes, inline caches, and specialized JITed code paths. When those assumptions are violated, the engine may read or write memory incorrectly. Skilled exploit authors can convert type confusion into primitives such as address leaks or arbitrary reads/writes, which are then used to bypass sandboxing or execute code. Historically, V8 type‑confusion and memory‑safety defects have been weaponized in targeted and broad attacks; that history explains why vendors prioritize these fixes.

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Confirming the fix and affected builds​

Google’s Chrome 142 promotion and subsequent stable updates list the patched builds for desktop platforms; Chrome 142.0.7444.59 (Linux) and 142.0.7444.59/60 (Windows) / 142.0.7444.60 (macOS) are the baseline rollout numbers where multiple V8 fixes landed, and later 142.x updates continued to address additional V8 items. Operators should compare installed browser version strings against the Chrome release notes to confirm whether their Chrome installations meet or exceed the fixed build. Crucially, the upstream Chrome fix does not immediately mean downstream safety. Microsoft Edge, Electron apps, kiosk/web‑appliance runtimes, and embedded WebView/CEF packages must each ingest the Chromium patch and ship updated binaries. Many enterprise devices and applications bundle a specific Chromium/V8 runtime and will remain vulnerable until the vendor releases a patched package. Treat the Chrome build number as the upstream signal and vendor advisories as the authority for downstream remediation status.

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Cross‑checks and verifiability​

Key public registries and trackers confirming the advisory include the NVD entry for CVE‑2025‑13226 and multiple independent vulnerability databases and vendor advisories that list the Chrome build boundary and severity. These independent sources agree on the essential facts: type confusion in V8, affected Chrome builds prior to 142.0.7444.59, and high operational impact. Where public sources disagree or withhold detail (for example, exploit technical data), that is typically deliberate to avoid accelerating mass exploitation until a majority of users are patched. If any claim cannot be corroborated in authoritative vendor pages or national vulnerability databases, it is flagged in the analysis below. Caveat: some news outlets conflate separate but related V8 CVEs (multiple V8 flaws were patched across Chrome 142.x) when reporting urgency; verify the exact CVE‑to‑build mapping for each variant in Chrome release notes and vendor security guides. Where downstream vendors list different ingestion boundaries, use the vendor’s advisory as the authoritative remediation signal for that product.

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Immediate remediation checklist (operational playbook)​

• Update Chrome installations to version 142.0.7444.59 or later on all desktops and servers that use Google Chrome. Ensure the browser is relaunched after the update to activate the patch.
• Inventory every Chromium‑based runtime in your environment:
• Microsoft Edge (desktop/mobile)
• Electron‑based applications (Slack, VS Code, Discord, many internal apps)
• Embedded WebView instances and WebView2 on Windows
• Kiosk systems, appliances, and thin clients that embed Chromium
• Server‑side headless browsers, rendering workers, and CI runners
  Use automated tools (software inventory, EDR, package managers) to detect bundled Chromium/V8 versions.
• Track downstream vendor bulletins and apply vendor‑shipped patches:
• For Microsoft Edge, consult the Microsoft Security Update Guide and Edge release notes to confirm ingestion of the Chromium fix before declaring Edge remediated.
• For Electron apps, check vendor update channels or reach out to ISVs for timelines.
• If rapid patching is not possible:
• Enforce URL filtering and proxy rules to block or scrutinize untrusted web content.
• Disable automatic rendering of third‑party or inline HTML in internal apps.
• Restrict web access for high‑risk users and service accounts.
• Enforce least privilege, remove local admin rights where not needed, and enable browser process mitigations where possible (site isolation, strict extension policies).
• For servers using headless Chromium, isolate those hosts, limit network egress, and consider temporary removal from production while fixes are applied.
• Coordinate forced restarts if necessary to ensure users pick up the patched binary. Browser updates only activate after relaunch, so staged restarts may be required for enterprise fleets.

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Detection, hunting, and forensic guidance​

• Look for unusual renderer process crashes or repeated tab restarts across endpoints. Mass crashes concentrated around web browsing or specific Electron apps can be a sign of attempted exploitation or active scanning.
• Query EDR telemetry for:
• Unexpected child processes spawned by chrome.exe, msedge.exe, or embedded renderer processes.
• Anomalous JIT compilation patterns or unusual memory allocations in browser processes.
• Sudden increases in outbound TLS sessions that begin immediately after visiting certain domains (possible exfiltration attempts after a successful compromise).
• Preserve evidence: if you suspect exploitation, collect process memory dumps, browser crash reports, and network capture for the time window around the event. Memory images are often needed to understand heap corruption exploitation attempts.
• Hunting heuristics:
• Search web gateway and proxy logs for new domains with spikes of traffic and short TTL patterns across user agents.
• Monitor for frequent renderer crashes across many hosts pointing to a malicious site or malvertising campaign.
• Use YARA‑style detections or heuristic signatures for known exploit payload shapes when they become available from trusted threat intel providers.

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Risk analysis: strengths and weaknesses of current posture​

Strengths​

• Chromium’s rapid upstream disclosure and patch cadence compresses exposure time; Google publishes Chrome releases and security notes promptly when memory‑safety issues are fixed.
• When a vulnerability is public and high‑impact, enterprise mechanisms (auto‑update, managed update channels, KEV/BOD guidance) exist to prioritize remediation and reduce dwell time. Vendor and community guidance gives operational playbooks for urgent patching.

Weaknesses / Risks​

• The primary operational risk is the supply‑chain lag: upstream Chrome fixes must propagate to downstream consumers (Microsoft Edge, Electron apps, embedded devices). Those downstream packages often lag and create exploitable windows for large classes of devices and applications. Attackers target those windows.
• Many organizations lack robust inventories of embedded Chromium runtimes. Unpatched Electron apps, admin consoles, or kiosk appliances are common blind spots and are frequently exploited when widespread browser patches are applied.
• Public reporting sometimes groups multiple related V8 CVEs together; that can obscure which exact builds fix which CVE. Precisely mapping CVEs to build numbers is essential for accurate patch verification.

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Technical deep dive: exploitation model and mitigations​

Exploitation model​

An attacker crafts HTML (and often accompanying JavaScript or WebAssembly) that exercises the V8 code path where type assumptions are violated. The exploit aims to:

• Produce deterministic memory corruption (heap or OOB write/read).
• Convert that corruption into a primitive (address leak, arbitrary read/write).
• Use the primitive to bypass sandboxing (for example, by corrupting internal pointers or vtables).
• Execute native payloads or escalate to system compromise.

The attack chain typically requires careful heap grooming and precise timing, but once reliable primitives exist, exploits become much easier to weaponize and scale. Historical V8 exploits demonstrate how quickly such primitives move from private research into commodity exploit kits when a reliable chain is found.

Language/runtime mitigations​

• Browser vendors implement mitigations such as site isolation, sandbox hardening, control‑flow integrity (CFI), and heap randomization to increase exploitation difficulty. These hardening measures raise the bar but do not eliminate risk, especially when bugs create powerful primitives.
• Runtime mitigations like JIT hardening and stricter subtyping checks inside V8 can be added upstream to reduce the attack surface for type confusion; those are often the code changes in Chrome security patches. When available, operators should enable recommended hardening flags in controlled environments to test impact before broad rollout.

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Long‑term operational recommendations​

• Adopt a comprehensive software bill‑of‑materials (SBOM) or runtime inventory practice that includes embedded runtimes (Electron, WebView, CEF). Detecting and tracking bundled Chromium versions is a prerequisite to remediation.
• Use managed update channels (WSUS, Intune, SCCM, EMM) to orchestrate staged updates and forced relaunches for browser fleets. Central control of update enforcement eliminates user-dependent delays that extend the exposure window.
• Build vendor‑agnostic patch playbooks: the incident response checklist should assume multiple vendors need to be updated (Chrome, Edge, Electron apps, appliance vendors) and map update owners, communications, and timelines clearly.
• Harden critical endpoints: restrict high‑risk user groups from general web browsing, limit plugin/extension installations via policy, and enable web content filtering at the network edge for high‑value assets.

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What to tell executives (concise brief)​

• CVE‑2025‑13226 is a high‑severity type‑confusion bug in Chromium’s V8 that can be triggered remotely by malicious web content. It affects Chrome builds prior to 142.0.7444.59 and represents a broad risk because many apps and devices embed the same runtime.
• Immediate action: update Chrome on all endpoints and inventory downstream Chromium consumers (Edge, Electron apps, WebView) to ensure they’ve applied equivalent fixes. If you cannot patch rapidly, implement network filtering and reduce exposure for sensitive groups.
• Operational impact: if unpatched, the vulnerability can be used to crash services and, in worst cases, achieve arbitrary code execution—leading to data theft, persistent compromise, or service denial. Prioritize remediation accordingly.

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Final verdict and caveats​

CVE‑2025‑13226 is a credible, high‑impact memory‑safety flaw that warrants urgent remediation. The upstream fix is chrome 142.0.7444.59 and later; however, remediation in a real environment requires more than updating Chrome itself. Enterprises must inventory, track, and patch every downstream consumer of Chromium/V8 in their environment to truly close the exposure window. Automated patch enforcement, enhanced telemetry hunts for browser process anomalies, and network controls for untrusted content will reduce immediate risk while vendors’ downstream updates propagate. Caveat: public reporting and advisory text may aggregate multiple V8 CVEs patched across Chrome 142; confirm the exact CVE‑to‑build mapping for each affected product as part of patch validation. Where definitive exploitation in the wild is not confirmed by vendor advisories, treat the risk as urgent nonetheless—type‑confusion V8 bugs historically escalate quickly from theoretical to practical exploits.

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If you manage endpoints, begin the remediation sequence now: verify Chrome builds, inventory embedded runtimes, apply vendor patches, and deploy compensating network and endpoint controls until every runtime is proven patched. The combination of fast upstream fixes and disciplined downstream ingestion is the only robust defense against this class of browser engine vulnerability.

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Source: MSRC Security Update Guide - Microsoft Security Response Center