CVE-2026-93045

bpf: Reject arena frees below the arena base

State: Published
Severity: 7.8 High
Published: Sep 17, 2026
Updated: Oct 19, 2026
Reserved: Sep 17, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject arena frees below the arena base

bpf_arena_free_pages() accepts scalar arena addresses. The runtime masks the address to the low 32 bits and reconstructs a full user address from the arena base before returning the range to the arena free tree.

When the scalar value is below the low 32 bits of the arena base, full_uaddr falls below user_vm_start. The existing upper-end clipping then turns this into an out-of-range free-tree offset. A later allocation can reuse that offset and return an address below the arena mapping.

Reject such frees before computing the clipped range.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	317460317a02a1af512697e6e964298dedd8a163 to before 90453eaf8f14e7be0ab03983f2a93aeb6b990a58Affected 317460317a02a1af512697e6e964298dedd8a163 to before a968dffa5ab3c74d2ebb3a6233bf8b843f0bfc20Affected 317460317a02a1af512697e6e964298dedd8a163 to before 8a08635656037aee9c12231ed384449c4ffb1a93Affected 317460317a02a1af512697e6e964298dedd8a163 to before b5a71cb2db6d84ac0042549dcec266b18429d41eAffected
LinuxLinux	6.9Affected before 6.9Not affected 6.12.110 through 6.12.Not affected 6.18.52 through 6.18.Not affected 7.2.6 through 7.2.*Not affected 7.3 and laterNot affected

References

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