CVE-2021-47328: scsi: iscsi: Fix conn use after free during resets

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-08-04
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: iscsi: Fix conn use after free during resets If we haven't done a unbind target call we can race where iscsi_conn_teardown wakes up the EH thread and then frees the conn while those threads are still accessing the conn ehwait. We can only do one TMF per session so this just moves the TMF fields from the conn to the session. We can then rely on the iscsi_session_teardown->iscsi_remove_session->__iscsi_unbind_session call to remove the target and it's devices, and know after that point there is no device or scsi-ml callout trying to access the session.

Affected products

Linux kernel: before 4.19.198; from 4.20 before 5.4.134; from 5.5 before 5.10.52; from 5.11 before 5.12.19; from 5.13 before 5.13.4 — fixed in 4.19.198, 5.10.52, 5.12.19, 5.13.4, 5.4.134

How to fix

Upgrade to a fixed version: Linux kernel 4.19.198, 5.10.52, 5.12.19, 5.13.4. Check the vendor advisory for mitigations.

References

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