CVE-2016-1646
Google Chromium V8 Out-of-Bounds Read Vulnerability
Description
CVE-2016-1646 is an out-of-bounds read vulnerability in the V8 JavaScript engine used by Google Chromium and multiple Chromium-based browsers including Google Chrome, Microsoft Edge, and Opera. The flaw allows a remote attacker to craft malicious JavaScript code that triggers an out-of-bounds memory read, potentially causing a denial of service or enabling further exploitation. Because V8 is shared across a wide range of modern browsers, CVE-2016-1646 has a broad attack surface. CISA has added this vulnerability to its Known Exploited Vulnerabilities catalog, and with an EPSS score of 68.4%, there is a high probability of active exploitation in the wild.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| debian | debian linux | 8.0; 9.0 |
| canonical | ubuntu linux | 14.04; 15.10; 16.04 |
| chrome | < 49.0.2623.108 | |
| suse | package hub | - |
| opensuse | leap | 42.1 |
| opensuse | opensuse | 13.1 |
| redhat | enterprise linux desktop | 6.0 |
| redhat | enterprise linux eus | 6.7 |
| redhat | enterprise linux server | 6.0 |
| redhat | enterprise linux workstation | 6.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://googlechromereleases.blogspot.com/2016/03/stable-channel-update_24.html(Release Notes, Vendor Advisory)
- http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00000.html(Mailing List, Third Party Advisory)
- http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00001.html(Mailing List, Third Party Advisory)
- http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00039.html(Mailing List, Third Party Advisory)
- http://rhn.redhat.com/errata/RHSA-2016-0525.html(Third Party Advisory)
- http://www.debian.org/security/2016/dsa-3531(Mailing List, Third Party Advisory)
- http://www.securitytracker.com/id/1035423(Broken Link, Third Party Advisory, VDB Entry)
- http://www.ubuntu.com/usn/USN-2955-1(Third Party Advisory)
- https://code.google.com/p/chromium/issues/detail?id=594574(Exploit, Issue Tracking, Mailing List)
- https://codereview.chromium.org/1804963002/(Patch)
- https://security.gentoo.org/glsa/201605-02(Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-1646(US Government Resource)
Weakness Type
CWE-125: Out-of-bounds Read
CVE-2016-1646 exploits an out-of-bounds read condition in the Chromium V8 JavaScript engine, where the engine fails to properly validate memory access boundaries during JavaScript execution. This allows an attacker to read data beyond the intended buffer limits, potentially exposing sensitive memory contents or causing the application to crash.
Learn more: CWE-125 — Out-of-bounds Read
Impact Analysis
CVE-2016-1646 is remotely exploitable without physical access, as an attacker only needs to lure a victim to a malicious web page containing crafted JavaScript code. The attack complexity is low since no special conditions or authentication are required — simply visiting the page is sufficient. The out-of-bounds read in V8 can expose sensitive information stored in adjacent memory regions, including internal state data or memory addresses that help defeat Address Space Layout Randomization (ASLR). Beyond information disclosure, the vulnerability may also enable denial of service by crashing the browser process. With an EPSS score of 68.4% (98th percentile), CVE-2016-1646 has a very high likelihood of exploitation, making it a priority for remediation across all organizations using Chromium-based browsers.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2016-1646 in the wild by adding it to the Known Exploited Vulnerabilities catalog on June 8, 2022, with a remediation deadline of June 22, 2022. The EPSS score of 68.4% places this vulnerability in the 98th percentile, indicating a very high probability of exploitation activity. While no ransomware association has been specifically reported for this vulnerability, the broad exposure of Chromium-based browsers and the availability of V8 engine internals to security researchers make exploit development feasible. Organizations running outdated versions of Chrome, Edge, or Opera should treat this as an urgent remediation priority.
Remediation
- Update all Chromium-based browsers immediately: Apply the latest updates per vendor instructions for Google Chrome, Microsoft Edge, Opera, and any other browsers utilizing the Chromium V8 engine to ensure the patched version of V8 is in use.
- Enable automatic browser updates: Configure all managed endpoints to receive automatic browser updates to minimize the window of exposure for V8 and other browser engine vulnerabilities.
- Implement browser isolation or sandboxing: Deploy browser isolation technology to contain potential exploitation of browser engine vulnerabilities, preventing lateral movement from a compromised renderer process.
- Review and restrict JavaScript execution: Consider deploying Content Security Policy headers and script-blocking extensions on high-value endpoints to limit exposure to malicious JavaScript on untrusted sites.
- Monitor for anomalous browser process behavior: Review endpoint detection logs for unusual V8 or renderer process crashes, memory access violations, or child process spawning that may indicate exploitation attempts.
Technical Details
CVE-2016-1646 resides in the V8 JavaScript engine, the core JavaScript execution component of Chromium. The vulnerability is triggered when the engine processes crafted JavaScript code that causes an out-of-bounds memory read — specifically, the engine accesses memory beyond the allocated buffer boundaries during certain operations. This out-of-bounds read can leak internal memory contents, such as heap metadata or object pointers, which could be used by an attacker to bypass ASLR and facilitate further exploitation. The vulnerability is categorized under CWE-125, as the root cause is a failure to enforce proper bounds checking on memory access operations within V8. Since V8 operates within Chromium's renderer process sandbox, a successful exploit would typically need to be combined with a sandbox escape to achieve full system compromise, but information leakage alone can be a critical stepping stone for chained exploit scenarios.
Frequently Asked Questions
Is CVE-2016-1646 being actively exploited?
Yes. CISA has confirmed active exploitation of CVE-2016-1646 by adding it to the Known Exploited Vulnerabilities catalog. The EPSS score of 68.4% further indicates a high probability of ongoing exploitation. Organizations should prioritize patching all Chromium-based browsers.
What products are affected by CVE-2016-1646?
CVE-2016-1646 affects the Google Chromium V8 JavaScript engine, which is used by multiple browsers including Google Chrome, Microsoft Edge, and Opera. Any application or browser built on the Chromium engine with an unpatched version of V8 is potentially vulnerable.
How do I fix CVE-2016-1646?
Update all Chromium-based browsers to the latest available version, which includes the patched V8 engine. Enable automatic updates and consider implementing browser isolation to contain potential exploitation attempts.
How severe is CVE-2016-1646?
CVE-2016-1646 is a significant vulnerability with an EPSS score in the 98th percentile. While the primary impact is an out-of-bounds read leading to information disclosure and denial of service, leaked memory data can facilitate more severe chained attacks. The broad usage of Chromium-based browsers amplifies the overall risk.
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