The latest security information on Intel® products.
Q2 2018 Speculative Execution Side Channel Update
Security researchers identified two software analysis methods that, if used for malicious purposes, have the potential to improperly gather sensitive data from multiple types of computing devices with different vendors’ processors and operating systems.
Intel is committed to product and customer security and to coordinated disclosure. We worked closely with other technology companies and several operating system and system software vendors, developing an industry-wide approach to mitigate these issues promptly.
For facts about these new methods, technical resources, and steps you can take to help protect your systems and information please visit: https://www.intel.com/securityfirst.
CVE-2018-3639 – Speculative Store Bypass (SSB) – also known as Variant 4
- Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the addresses of all prior memory writes are known may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis.
- 4.3 Medium CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
CVE-2018-3640 – Rogue System Register Read (RSRE) – also known as Variant 3a
- Systems with microprocessors utilizing speculative execution and that perform speculative reads of system registers may allow unauthorized disclosure of system parameters to an attacker with local user access via a side-channel analysis.
- 4.3 Medium CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Please check with your system vendor or equipment manufacturer for more information regarding updates for your system. For non-Intel based systems please contact your system manufacturer or microprocessor vendor.
A list of impacted products can be found here.
Most leading browser providers have recently deployed mitigations in their Managed Runtimes – mitigations that substantially increase the difficulty of exploiting side channels in a modern web browser. These techniques would likewise increase the difficulty of exploiting a side channel in a browser based on SSB.
Intel has released Beta microcode updates to operating system vendors, equipment manufacturers, and other ecosystem partners adding support for Speculative Store Bypass Disable (SSBD). SSBD provides additional protection by providing a means for system software to completely inhibit a Speculative Store Bypass from occurring if desired. This is documented in whitepapers located at Intel’s Software Side-Channel Security site. Most major operating system and hypervisors will add support for Speculative Store Bypass Disable (SSBD) starting as early as May 21, 2018.
The microcode updates will also address Rogue System Register Read (RSRR) – CVE-2018-3640 by ensuring that RDMSR instructions will not speculatively return data under certain conditions. This is documented in whitepapers located at Intel’s Software Side-Channel Security site. No operating system or hypervisor changes are required to support the RDMSR change.
A listing of microcode updates that have been production qualified can be found here and will be updated as necessary. It is expected that remaining microcode updates, currently in beta, will be production qualified in the coming weeks. Intel recommends end users and systems administrators check with their OEM and system software vendors and apply any available updates as soon as practical.
Additional Advisory Guidance on CVE-2018-3639 available here.
Intel would like to acknowledge and thank Jann Horn of Google Project Zero (GPZ) and Ken Johnson of the Microsoft Security Response Center (MSRC) for independently reporting CVE-2018-3639.
Intel would like to acknowledge and thank Zdenek Sojka, Rudolf Marek and Alex Zuepke from SYSGO AG (https://sysgo.com) for reporting CVE-2018-3640. Intel would also like to acknowledge and thank Innokentiy Sennovskiy from BiZone LLC (bi.zone).
Intel would like to thank Kekai Hu, Ke Sun, Henrique Kawakami and Rodrigo Branco for CVE-2018-3639 and CVE-2018-3640.
|1.0||May 21, 2018||Initial Release|
|1.1||June 21, 2018||Updated Recommendations|
|1.2||July 22, 2019||Updated Acknowledgements|
|1.3||September 29, 2020||Updated Affected Products|
|1.4||05/11/2021||Added CVE Additional Guidance Link|
CVE Name: CVE-2018-3639, CVE-2018-3640
Legal Notices and Disclaimers
Intel provides these materials as-is, with no express or implied warranties.
All products, dates, and figures specified are preliminary based on current expectations, and are subject to change without notice.
Intel, processors, chipsets, and desktop boards may contain design defects or errors known as errata, which may cause the product to deviate from published specifications. Current characterized errata are available on request.
Intel technologies’ features and benefits depend on system configuration and may require enabled hardware, software or service activation. Performance varies depending on system configuration. No product or component can be absolutely secure. Check with your system manufacturer or retailer or learn more at https://intel.com.
Some results have been estimated or simulated using internal Intel analysis or architecture simulation or modeling, and provided to you for informational purposes. Any differences in your system hardware, software or configuration may affect your actual performance.
Intel and the Intel logo are trademarks of Intel Corporation in the United States and other countries.
*Other names and brands may be claimed as the property of others.
Copyright © Intel Corporation 2022
Report a Vulnerability
If you have information about a security issue or vulnerability with an Intel branded product or technology, please send an e-mail to email@example.com. Encrypt sensitive information using our PGP public key.
Please provide as much information as possible, including:
- The products and versions affected
- Detailed description of the vulnerability
- Information on known exploits
A member of the Intel Product Security Team will review your e-mail and contact you to collaborate on resolving the issue. For more information on how Intel works to resolve security issues, see:
For issues related to Intel's external web presence (Intel.com and related subdomains), please contact Intel's External Security Research team.