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TI-2021-11823 Aliases CVE-2021-31829GHSA-f8g9-h6rj-mq5j

kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative…

Priority LOW 25CWE-863Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
Partial Red Hat: 4 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-863.

Summary

kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads, leading to disclosure of stack content via side-channel attacks, aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also, the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel.

Why it matters now

EPSS 0.00313 24th percentileScored 2026-11-07
Fix Partial Red Hat: 2 advisoriesRed Hat: 4 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*up to 5.12.1VulnerableLinux
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*32VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions up to 5.12.1 Vulnerable ·Linux
  • cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian

Remediation

Red Hat 2 advisories

  • RHSA-2021:4356 Released 2021-11-09 · Red Hat rating Moderate
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-348.el8
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-348.el8, kernel-4.18.0-348.el8, kernel-abi-stablelists-4.18.0-348.el8 +19
  • RHSA-2021:4140 Released 2021-11-09 · Red Hat rating Moderate
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt-4.18.0-348.rt7.130.el8, kernel-rt-core-4.18.0-348.rt7.130.el8, kernel-rt-debug-4.18.0-348.rt7.130.el8 +7
    • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-348.rt7.130.el8, kernel-rt-core-4.18.0-348.rt7.130.el8, kernel-rt-debug-4.18.0-348.rt7.130.el8 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 7AffectedNo fix planned: Will not fix
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2021:4356
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2021:4356
Red Hat Enterprise Linux Real Time (v. 8)Fixed RHSA-2021:4140
Red Hat Enterprise Linux Real Time for NFV (v. 8)Fixed RHSA-2021:4140
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-31829
  2. 2026-10-03 Alias added: GHSA-f8g9-h6rj-mq5j

References

Patch 2

Advisory 4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences