CVE-2021-47317

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.

CVSS v3.1 Score

3.3

LOW

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

Weakness Type (CWE)

CWE-667 CWE-667

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.12 — 5.12.19
linux	linux_kernel	5.13 — 5.13.4

References

Advisories & Patches

https://git.kernel.org/stable/c/0d435b6d94b05dcfd836d758a63145aa566618e2 https://git.kernel.org/stable/c/419ac821766cbdb9fd85872bb3f1a589df05c94c https://git.kernel.org/stable/c/7284dab07e4d51d453cc42851fae9ec4fac6ef2f https://git.kernel.org/stable/c/0d435b6d94b05dcfd836d758a63145aa566618e2 https://git.kernel.org/stable/c/419ac821766cbdb9fd85872bb3f1a589df05c94c https://git.kernel.org/stable/c/7284dab07e4d51d453cc42851fae9ec4fac6ef2f

Frequently Asked Questions

What is CVE-2021-47317? +

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. It has a CVSS v3.1 base score of 3.3 (LOW).

How severe is CVE-2021-47317? +

CVE-2021-47317 has a CVSS v3.1 score of 3.3 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

What products are affected by CVE-2021-47317? +

CVE-2021-47317 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47317? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-1221

A Zigbee Radio Co-Processor (RCP), which is using SiLabs EmberZNet Zigbee stack, was unable to send messages to the host …

CVE-2025-10151

Improper locking vulnerability in Softing Industrial Automation GmbH gateways allows infected memory and/or resource leak exposure.This issue affects smartLink HW-PN: …

CVE-2026-54906 9.8

concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#release_write_lock does not verify that the calling thread acquired …

CVE-2026-43215 8.8

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to …

CVE-2026-31629 8.8

In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: add missing return after LLCP_CLOSED checks In nfc_llcp_recv_hdlc() …

CVE-2021-22530 8.2

A vulnerability identified in NetIQ Advance Authentication that doesn't enforce account lockout when brute force attack is performed on API …