CVE intelligence and bounded remediation

CVE-2021-31829 — Linux Linux Kernel security vulnerability

Medium CVSS 5.5

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.

Severity
Medium
CVSS
5.5 (3.1)
Published
2021-05-06
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-863

Affected products

  • linux / linux_kernel
  • fedoraproject / fedora / 32
  • fedoraproject / fedora / 33
  • fedoraproject / fedora / 34
  • debian / debian_linux / 9.0

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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