NVD / CVE Program· CNA Linux

CVE-2021-47317: powerpc/bpf: Fix detecting BPF atomic instructions

LowCVSS 3.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 13/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 0d435b6d94b05dcfd836d758a63145aa566618e2, 419ac821766cbdb9fd85872bb3f1a589df05c94c, 7284dab07e4d51d453cc42851fae9ec4fac6ef2f.
Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 3.3.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0d435b6d94b05dcfd836d758a63145aa566618e2, 419ac821766cbdb9fd85872bb3f1a589df05c94c, 7284dab07e4d51d453cc42851fae9ec4fac6ef2f or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Denial of service

BDU:2025-14370

Published: May 21, 2024
Updated: Aug 5, 2026
EPSS: 0.1% · 8th percentile
CWE: CWE-667

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 13 / 40 · 3.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 3.3
CNA · Linux: 7.8; 4.5 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 5.12affected
- 91c960b0056672e74627776655c926388350fa30 and later · before 7284dab07e4d51d453cc42851fae9ec4fac6ef2faffected · git
- 91c960b0056672e74627776655c926388350fa30 and later · before 0d435b6d94b05dcfd836d758a63145aa566618e2affected · git
- 91c960b0056672e74627776655c926388350fa30 and later · before 419ac821766cbdb9fd85872bb3f1a589df05c94caffected · git
- before 5.12not affected · semver
- 5.12.19 and later · up to and including 5.12.*not affected · semver
- 5.13.4 and later · up to and including 5.13.*not affected · semver
- 5.14 and laternot affected · original_commit_for_fix

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel5.12 and later · before 5.12.19
linux linux kernel5.13 and later · before 5.13.4

Same product

linux: all records

Other highest-scoring records for the same primary product.

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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
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Published before and after this one in the same product

← EarlierCVE-2021-47314May 21, 2024 · memory: fsl_ifc: fix leak of private memory on probe failure
22Monitor
← EarlierCVE-2021-47315May 21, 2024 · memory: fsl_ifc: fix leak of IO mapping on probe failure
22Monitor
Later →CVE-2021-47318May 21, 2024 · arch_topology: Avoid use-after-free for scale_freq_data
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	0d435b6d94b05dcfd836d758a63145aa566618e2	Vendor (CNA)
Linux Linux	419ac821766cbdb9fd85872bb3f1a589df05c94c	Vendor (CNA)
Linux Linux	7284dab07e4d51d453cc42851fae9ec4fac6ef2f	Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.