Disclosure summary
In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects the possibility of uninitialized memory locations on the BPF stack.
Source-reported weakness categories
CWE-203
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2021-34556
Open original source · Updated Oct 08, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
| Vendor | Product / association | Version / bounds |
|---|---|---|
| linux | linux_kernel | * {"versionEndIncluding":"5.13.7"} |
| fedoraproject | fedora | 33 |
| fedoraproject | fedora | 34 |
| debian | debian_linux | 9.0 |
Original records & references
- NIST NVD record
- CVE Program record
- git.kernel.org — Patch, Vendor Advisory
- git.kernel.org — Patch, Vendor Advisory
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org
- lists.fedoraproject.org
- git.kernel.org — Patch, Vendor Advisory
- git.kernel.org — Patch, Vendor Advisory
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org
- lists.fedoraproject.org
PUBLISHED 2021-08-02T01:15:07-04:00
MODIFIED 2026-10-08T17:17:35-04:00
INGESTED 2026-10-10T20:50:20-04:00