CVE-2024-36891: maple_tree: fix mas_empty_area_rev() null pointer dereference

Severity: medium (CVSS 5.5 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: 2024-05-30 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: maple_tree: fix mas_empty_area_rev() null pointer dereference Currently the code calls mas_start() followed by mas_data_end() if the maple state is MA_START, but mas_start() may return with the maple state node == NULL. This will lead to a null pointer dereference when checking information in the NULL node, which is done in mas_data_end(). Avoid setting the offset if there is no node by waiting until after the maple state is checked for an empty or single entry state. A user could trigger the events to cause a kernel oops by unmapping all vmas to produce an empty maple tree, then mapping a vma that would cause the scenario described above.

Affected products

Linux kernel: from 6.1 before 6.6.31; from 6.7 before 6.8.10 — fixed in 6.6.31, 6.8.10

How to fix

Upgrade to a fixed version: Linux kernel 6.6.31, 6.8.10. Check the vendor advisory for mitigations.

References

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