The latest security information on Intel® products.

Intel® Processors Return Stack Buffer Underflow Advisory

Intel ID: INTEL-SA-00702
Advisory Category: Hardware
Impact of vulnerability: Information Disclosure
Severity rating: MEDIUM
Original release: 07/12/2022
Last revised: 07/12/2022

Summary: 

A potential security vulnerability in some Intel® Processors may allow information disclosure.  Intel is releasing prescriptive guidance to address this potential vulnerability.

Vulnerability Details:

CVEID:  CVE-2022-29901

Description: Non-transparent sharing of branch predictor targets between contexts in some Intel(R) Processors may allow an authorized user to potentially enable information disclosure via local access.

CVSS Base Score:  4.7 Medium

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

Affected Products:

Some Intel® Processors, consult this list of affected products here.

Recommendations:

Intel recommends that affected Intel® Processors use Indirect Branch Restricted Speculation (IBRS) instead of ‘retpoline’ to address this potential vulnerability.  Intel is releasing a technical paper to describe the Return Stack Buffer Underflow recommendation.

Intel has worked with operating system vendors to develop software updates to address this potential vulnerability.

Intel has worked with the Linux community to make this option available to all Linux users. Systems administrators and end users should check with their Linux vendor to determine the status of the operating system fix.

Windows operating system uses IBRS by default, so no update is required.

Previously ‘retpoline’ and IBRS are described as part of the technical paper listed here:

https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/retpoline-branch-target-injection-mitigation.html

Acknowledgements:

Intel would like to thank Johannes Wikner and Kaveh Razavi from the COMSEC group at ETH Zurich for reporting this issue.

Intel, and nearly the entire technology industry, follows a disclosure practice called Coordinated Disclosure, under which a cybersecurity vulnerability is generally publicly disclosed only after mitigations are available.

Revision History

Revision Date Description
1.0 07/12/2022 Initial Release

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 secure@intel.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.

Need product support?

If you...

  • Have questions about the security features of an Intel product
  • Require technical support
  • Want product updates or patches


Please visit Support & Downloads.