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Chrome 140 Bolsters Security with Six CVEs Fixed and RCE Mitigated

Redoracle TeamOriginal9/4/25About 6 minNewschromevulnerabilitiesrcev8patchbug-bountyfuzzingsanitizersvulnerability-disclosureresearchersrolloutextended-stabletoolbarextensionsdownloadsbrowsers

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Introduction

Chrome 140 bolsters security with six CVEs fixed and remote code execution risk mitigated. This release reinforces Chrome's multi-layered defense approach combining patch management, bug-bounty collaboration, fuzzing, and sanitizer-driven discovery. Keywords integrated throughout: chrome vulnerabilities rce v8 patch bug-bounty fuzzing sanitizers vulnerability-disclosure researchers rollout extended-stable toolbar extensions downloads browsers.

Executive Summary

  • Google released Chrome 140 to the stable channel for Windows Mac and Linux with targeted security improvements and a staged rollout across channels.
  • Build versions: Linux 140.0.7339.80; Windows and macOS 140.0.7339.80 and 140.0.7339.81; Extended Stable Channel for Windows and macOS receives 140.0.7339.81.
  • Six security fixes included one high severity use-after-free in the V8 JavaScript engine identified as CVE-2025-9864 which could enable remote code execution and potential data compromise.
  • Three of the six fixes came from external researchers under Google’s vulnerability rewards program with monetary awards ranging from 1,000 to 5,000 USD.
  • Internal remediation consolidated as ID 442611697 addresses multiple issues surfaced by AddressSanitizer MemorySanitizer UndefinedBehaviorSanitizer Control Flow Integrity libFuzzer and AFL.

Key Highlights

  • High severity CVE-2025-9864 reported by Pavel Kuzmin of the Yandex Security Team on 2025-07-28 describes a use-after-free in V8 enabling possible remote code execution.
  • Medium severity CVE-2025-9865 reported by Khalil Zhani on 2025-08-07 involves an inappropriate implementation in the Toolbar component reward 5,000 USD.
  • Medium severity CVE-2025-9866 reported by NDevTK on 2024-11-16 affects the Extensions system reward 4,000 USD.
  • Medium severity CVE-2025-9867 reported by Farras Givari on 2025-05-04 concerns the Downloads component reward 1,000 USD.
  • Internal combined fix ID 442611697 addresses multiple sanitizer and fuzzing findings across the codebase.

What Changed and Who Reported the Vulnerabilities

  • Six security fixes were integrated into Chrome 140. Three were externally reported via the vulnerability-disclosure and bug-bounty process.
  • CVE-2025-9864 High severity use-after-free in V8 reported by Pavel Kuzmin Yandex Security Team on 2025-07-28. Impact includes potential remote execution of arbitrary code data exfiltration and system compromise.
  • CVE-2025-9865 Medium severity inappropriate implementation in Toolbar reported by Khalil Zhani on 2025-08-07 reward 5,000 USD.
  • CVE-2025-9866 Medium severity issue in Extensions reported by NDevTK on 2024-11-16 reward 4,000 USD.
  • CVE-2025-9867 Medium severity bug in Downloads reported by Farras Givari on 2025-05-04 reward 1,000 USD.
  • Internal efforts produced a consolidated fix ID 442611697 addressing issues uncovered by AddressSanitizer MemorySanitizer UndefinedBehaviorSanitizer Control Flow Integrity libFuzzer and AFL.

Release Details Versions Channels and Rollout

  • Linux receives 140.0.7339.80.
  • Windows and macOS receive 140.0.7339.80 and 140.0.7339.81.
  • Extended Stable Channel for Windows and macOS receives 140.0.7339.81.
  • Release notes and the Chromium release logs document the full changelog and security attributions.
  • Rollout is staged; updates will propagate progressively to end users over days and weeks as devices check for updates.

Security Fixes and CVEs Detailed

  • CVE-2025-9864 Severity High Use-after-free in V8
    • Reporter Pavel Kuzmin Yandex Security Team reported 2025-07-28.
    • Affects V8 JavaScript engine memory management leading to potential remote code execution.
    • Consequences include arbitrary code execution and possible data theft or system compromise.
    • Reward listed as Not Applicable in the provided table but issue acknowledged as critical.
  • CVE-2025-9865 Severity Medium Toolbar inappropriate implementation
    • Reporter Khalil Zhani reported 2025-08-07 reward 5,000 USD.
    • UI component related vulnerability with potential security implications through state or input handling.
  • CVE-2025-9866 Severity Medium Extensions subsystem
    • Reporter NDevTK reported 2024-11-16 reward 4,000 USD.
    • Vulnerability affects extension handling and integrity controls.
  • CVE-2025-9867 Severity Medium Downloads component
    • Reporter Farras Givari reported 2025-05-04 reward 1,000 USD.
    • Bug impacts download workflows and file handling state transitions.
  • Internal Fix ID 442611697
    • Consolidates multiple fixes resulting from sanitizer and fuzzing pipelines.
    • Tools involved AddressSanitizer MemorySanitizer UndefinedBehaviorSanitizer Control Flow Integrity libFuzzer AFL.
    • Reflects Google’s automation assisted security testing and remediation processes.

Researchers Rewards and Disclosure

  • Google’s vulnerability rewards program incentivizes responsible disclosure and contributes to timely fixes.
  • Reward scale here spans 1,000 to 5,000 USD reflecting severity and exploitability considerations.
  • External contributors in this release include Pavel Kuzmin Yandex Security Team Khalil Zhani NDevTK and Farras Givari.
  • Internal security teams use sanitizers and fuzzing to find issues preemptively and to complement external reports.

Internal Fixes and Security Practices

  • Chrome’s security workflow leverages a combination of static analysis dynamic sanitizers fuzzing and CFI.
  • AddressSanitizer MemorySanitizer and UndefinedBehaviorSanitizer detect memory safety and undefined behavior concerns.
  • libFuzzer and AFL provide fuzzing coverage to uncover edge case inputs and logic flaws.
  • Control Flow Integrity reinforces runtime protections to reduce exploitability of memory errors.
  • Consolidated internal patching and cross-team code review implement defense-in-depth to reduce RCE exposure.

Timeline of Events

  • 2024-11-16 NDevTK reports CVE-2025-9866 affecting Extensions system.
  • 2025-05-04 Farras Givari reports CVE-2025-9867 in Downloads component.
  • 2025-07-28 Pavel Kuzmin Yandex Security Team reports CVE-2025-9864 V8 use-after-free.
  • 2025-08-07 Khalil Zhani reports CVE-2025-9865 Toolbar issue.
  • 2025-09-03 Chrome 140 released to stable channel for Windows Mac and Linux builds 140.0.7339.80 and 140.0.7339.81; Extended Stable Channel receives variant 140.0.7339.81.
  • Post-release internal patch ID 442611697 consolidated sanitizer and fuzzing based fixes.

Impact Implications and Strategic Significance

  • The V8 use-after-free CVE-2025-9864 represents the most critical threat in this release given its RCE potential against browsers which are high value attack targets.
  • Fixes across Toolbar Extensions and Downloads reduce attack surface across UI extension and file handling vectors in browsers.
  • Monetary rewards and public disclosures foster coordinated vulnerability-disclosure and improve ecosystem resilience.
  • Sanitizer and fuzzing driven findings demonstrate a mature automation assisted security posture and continuous integration with security testing.

Stakeholders and Meaningful Actors

  • Google Security Team coordinates remediation integrates patches and manages disclosure timelines.
  • External researchers Pavel Kuzmin Yandex Security Team Khalil Zhani NDevTK and Farras Givari contributed reports that led to several CVE fixes and rewards.
  • End-users organizations and developers using Chrome benefit from reduced RCE risk.
  • Security research community and tooling ecosystems AddressSanitizer MemorySanitizer UBSan CFI libFuzzer AFL drive discovery and validation workflows.

Technical Insights and Deeper Analysis

  • V8 use-after-free issues highlight the persistent challenge of memory-safety in high performance JavaScript runtimes where manual memory management and complex GC interactions raise exploitation risk.
  • Toolbar component vulnerabilities illustrate that UI subsystems can contain exploitable flaws when state management input validation or implementation choices are weak.
  • Extensions system flaws underscore the need for robust sandboxing permission models and integrity checks to limit compromise vectors in third-party add-ons.
  • Downloads related bugs emphasize secure parsing validation and isolation of file handling subsystems to prevent chainable exploit scenarios.
  • The internal fix ID 442611697 shows practical benefits of combining sanitizers with fuzzers to detect both memory errors and logical corner cases before public exploitation.

Takeaways for Stakeholders

  • Timely patching of Chrome 140 is essential to mitigate known RCE exposures especially CVE-2025-9864 in V8.
  • Bug-bounty programs accelerate responsible disclosure and reward external researchers for identifying impactful vulnerabilities.
  • A multi-faceted security program uniting sanitizers fuzzing and collaborative disclosure reduces windows of exposure for browsers.
  • Organizations should track rollout and Extended Stable Channel variants 140.0.7339.81 for enterprise deployments.

Detailed Analysis

  • Attack surface analysis
    • V8 engine remains a high value target due to script execution privileges within the browser sandbox. Memory-corruption issues such as use-after-free can be weaponized into RCE chains especially when combined with JIT and type confusions.
    • UI components and feature subsystems such as Toolbar Extensions and Downloads present secondary yet meaningful surfaces where incorrect implementations can escalate privileges or enable sandbox escapes via complex exploitation chains.
  • Exploitability factors
    • Exploitability depends on allocation patterns garbage collector behavior mitigations like CFI and hardening layers present in modern Chrome builds and platform level protections.
    • Sanitizers and fuzzers lower the probability of unnoticed vulnerabilities but do not eliminate zero day risk which justifies continued investment in layered mitigations.
  • Organizational implications
    • Enterprises relying on Extended Stable Channel should plan for variant 140.0.7339.81 and validate compatibility with managed policies and extensions.
    • Security teams should correlate CVE details with internal risk models to prioritize update deployment for high exposure endpoints.
  • Research ecosystem implications
    • Monetary rewards for medium severity issues indicate incentive alignment for researchers to surface diverse classes of bugs not limited to RCE.
    • Continued investment in fuzzing infrastructure and sanitizer instrumentation yields recurring discovery of subtle memory and logic flaws.

Fact Checking and Sources

Relevant source materials strictly related to this release and the summarized CVEs include

Please consult the Chromium release notes and the official Chrome stable-channel update post for authoritative changelog entries and CVE attributions.

Question for Readers

Which aspect of Chrome 140 do you consider most significant for your organization security posture V8 engine hardening UI component fixes or the sanitizer and fuzzing driven internal patch

Conclusion

Chrome 140 delivers a focused set of security fixes that collectively mitigate remote code execution risk and harden multiple browser subsystems. The release highlights coordinated vulnerability-disclosure efforts between external researchers and Google internal teams supported by bug-bounty incentives and automated sanitizer and fuzzing pipelines. For chrome users and organizations the combined effect is meaningful reduction in exploitability across v8 toolbar extensions and downloads components and a continued demonstration of security engineering practices centered on defense-in-depth.

Summary Chrome 140 Bolsters Security with Six CVEs Fixed and RCE Mitigated

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