CVE-2023-52980: block: ublk: extending queue_size to fix overflow

Severity: high (CVSS 7.8 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: 2025-03-27 · updated 2026-06-17
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: block: ublk: extending queue_size to fix overflow When validating drafted SPDK ublk target, in a case that assigning large queue depth to multiqueue ublk device, ublk target would run into a weird incorrect state. During rounds of review and debug, An overflow bug was found in ublk driver. In ublk_cmd.h, UBLK_MAX_QUEUE_DEPTH is 4096 which means each ublk queue depth can be set as large as 4096. But when setting qd for a ublk device, sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io) will be larger than 65535 if qd is larger than 2728. Then queue_size is overflowed, and ublk_get_queue() references a wrong pointer position. The wrong content of ublk_queue elements will lead to out-of-bounds memory access. Extend queue_size in ublk_device as "unsigned int".

Affected products

Linux kernel: from 6.0 before 6.1.11; 6.2-rc1, 6.2-rc2, 6.2-rc3, 6.2-rc4, 6.2-rc5, 6.2-rc6 — fixed in 6.1.11

How to fix

Upgrade to a fixed version: Linux kernel 6.1.11. Check the vendor advisory for mitigations.

References

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