powerpc/bpf: Fix detecting BPF atomic instructions (CVE-2021-47317) | HOL Guard CVE

High · CVSS 7.8CVE-2021-47317

powerpc/bpf: Fix detecting BPF atomic instructions

Answer in brief

CVE-2021-47317 records a High severity (CVSS 7.8) vulnerability in powerpc/bpf: Fix detecting BPF atomic instructions. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published May 21, 2024Updated Aug 5, 2026Source checked Sep 19, 2026First seen by HOL Aug 4, 2026Material review Aug 5, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=91c960b0056672e74627776655c926388350fa30 <7284dab07e4d51d453cc42851fae9ec4fac6ef2f \|\| >=91c960b0056672e74627776655c926388350fa30 <0d435b6d94b05dcfd836d758a63145aa566618e2 \|\| >=91c960b0056672e74627776655c926388350fa30 <419ac821766cbdb9fd85872bb3f1a589df05c94c	7284dab07e4d51d453cc42851fae9ec4fac6ef2f, 0d435b6d94b05dcfd836d758a63145aa566618e2, 419ac821766cbdb9fd85872bb3f1a589df05c94c
Linux/Linuxgeneric	5.12	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 7284dab07e4d51d453cc42851fae9ec4fac6ef2f if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
May 21, 2024
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 4, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: powerpc/bpf: Fix detecting BPF atomic instructions Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other atomics in .imm") converted BPF_XADD to BPF_ATOMIC and added a way to distinguish instructions based on the immediate field. Existing JIT implementations were updated to check for the immediate field and to reject programs utilizing anything more than BPF_ADD (such as BPF_FETCH) in the immediate field. However, the check added to powerpc64 JIT did not look at the correct BPF instruction. Due to this, such programs would be accepted and incorrectly JIT'ed resulting in soft lockups, as seen with the atomic bounds test. Fix this by looking at the correct immediate value.

Quoted source text, attributed separately from HOL analysis.