CVE-2022-49870: capabilities: fix undefined behavior in bit shift for CAP_TO_MASK

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-01 · updated 2026-06-17
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c cap_task_prctl+0x561/0x6f0 security_task_prctl+0x5a/0xb0 __x64_sys_prctl+0x61/0x8f0 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK>

Affected products

Linux kernel: from 2.6.25 before 4.9.334; from 4.10 before 4.14.300; from 4.15 before 4.19.267; from 4.20 before 5.4.225; from 5.5 before 5.10.155; from 5.11 before 5.15.79 — fixed in 4.14.300, 4.19.267, 4.9.334, 5.10.155, 5.15.79, 5.4.225

How to fix

Upgrade to a fixed version: Linux kernel 4.14.300, 4.19.267, 4.9.334, 5.10.155. Check the vendor advisory for mitigations.

References

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