CVE-2023-52449: mtd: Fix gluebi NULL pointer dereference caused by ftl notifier

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: 2024-02-22 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: mtd: Fix gluebi NULL pointer dereference caused by ftl notifier If both ftl.ko and gluebi.ko are loaded, the notifier of ftl triggers NULL pointer dereference when trying to access ‘gluebi->desc’ in gluebi_read(). ubi_gluebi_init ubi_register_volume_notifier ubi_enumerate_volumes ubi_notify_all gluebi_notify nb->notifier_call() gluebi_create mtd_device_register mtd_device_parse_register add_mtd_device blktrans_notify_add not->add() ftl_add_mtd tr->add_mtd() scan_header mtd_read mtd_read_oob mtd_read_oob_std gluebi_read mtd->read() gluebi->desc - NULL Detailed reproduction information available at the Link [1], In the normal case, obtain gluebi->desc in the gluebi_get_device(), and access gluebi->desc in the gluebi_read(). However, gluebi_get_device() is not executed in advance in the ftl_add_mtd() process, which leads to NULL pointer dereference. The solution for the gluebi module is to run jffs2 on the UBI volume without considering working with ftl or mtdblock [2]. Therefore, this problem can be avoided by preventing gluebi from creating the mtdblock device after creating mtd partition of the type MTD_UBIVOLUME.

Affected products

Linux kernel: from 2.6.31 before 4.19.306; from 4.20 before 5.4.268; from 5.5.0 before 5.10.209; from 5.11.0 before 5.15.148; from 5.16.0 before 6.1.75; from 6.2.0 before 6.6.14 — fixed in 4.19.306, 5.10.209, 5.15.148, 5.4.268, 6.1.75, 6.6.14

How to fix

Upgrade to a fixed version: Linux kernel 4.19.306, 5.10.209, 5.15.148, 5.4.268. Check the vendor advisory for mitigations.

References

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