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CVE-2021-34556 Moderate

CVE-2021-34556

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects the possibility of uninitialized memory locations on the BPF stack.

Exploit probability 0.4%
Published August 2, 2021
Required by Not available
Last source change April 16, 2026

02 / AFFECTED SOFTWARE

Affected packages

Android :linux_kernel:

1 explicit affected versions

Unknown Unknown

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities PUB-A-196011539

In check_stack_write_fixed_off and related functions of verifier.c, there is a possible out of bounds read due to side channel information disclosure. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.

View original source
Open Source Vulnerabilities CVE-2021-34556

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects the possibility of uninitialized memory locations on the BPF stack.

View original source

05 / REFERENCES

Further evidence