CVE-2026-72084
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Vulnerability report for CVE-2026-72084, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: target: Bound PR-OUT TransportID parsing to the received buffer core_scsi3_decode_spec_i_port() and core_scsi3_emulate_register_and_move() hand the raw PERSISTENT RESERVE OUT parameter buffer to target_parse_pr_out_transport_id() without telling it how many bytes are valid. For an iSCSI TransportID (FORMAT CODE 01b), iscsi_parse_pr_out_transport_id() locates the ",i,0x" ISID separator with an unbounded strstr() (and on the error path prints the name with a further unbounded "%s"). An initiator can submit a TransportID whose iSCSI name contains neither a ",i,0x" substring nor a NUL terminator, filling the parameter list to its end, so the scan runs off the end of the buffer. When the parameter list spans more than one page the buffer is a multi-page vmap (transport_kmap_data_sg()), so the over-read walks into the trailing vmalloc guard page and oopses (KASAN: vmalloc-out-of-bounds in strstr). It is reachable by any fabric that delivers a PR OUT to a device exported through an iSCSI TPG, including a guest via vhost-scsi. Pass the number of received bytes down to the parser and validate the iSCSI TransportID's own self-described length (ADDITIONAL LENGTH + 4) once, up front: reject it if it is below the spc4r17 minimum or larger than the received buffer, then bound the separator search, the ISID walk and the name copy by that length. This is the length check the callers already perform after the parse (core_scsi3_decode_spec_i_port() compares tid_len against tpdl, core_scsi3_emulate_register_and_move() validates it against data_length), moved ahead of the scan. Also drop the unbounded "%s" of the unterminated name. Add per-format explicit name-length checks before copying into i_str, rather than silently truncating with min_t: for FORMAT CODE 00b reject if the descriptor body (tid_len - 4 bytes) cannot fit in i_str[TRANSPORT_IQN_LEN]; for FORMAT CODE 01b reject if the name portion (from &buf[4] up to the separator) cannot fit. Both checks make the bounds intent explicit at each format branch. While here, also reject a FORMAT CODE 01b TransportID whose ",i,0x" separator sits at the very end of the descriptor: that leaves an empty ISID and points the returned port nexus pointer at buf + tid_len, one past the descriptor, which the registration code (__core_scsi3_locate_pr_reg(), __core_scsi3_alloc_registration()) then dereferences as the ISID string -- the same over-read of the parameter buffer for a malformed descriptor.

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a buffer over-read vulnerability in the Linux kernel's SCSI target subsystem. It occurs when parsing PR-OUT TransportID parameters in iSCSI connections. The parser uses unbounded string operations (strstr) without validating buffer lengths, allowing an attacker to read beyond the allocated memory by crafting a malformed TransportID. This leads to a kernel oops (crash) when the over-read hits a vmalloc guard page.

Detection Guidance

This vulnerability is specific to the Linux kernel's SCSI target subsystem and is triggered by malformed iSCSI TransportID parameters. Detection requires checking kernel logs for KASAN vmalloc-out-of-bounds errors or system crashes related to strstr() over-reads in target_parse_pr_out_transport_id(). Examine logs with 'dmesg | grep -i kasan' or 'journalctl -k | grep -i oops'.

Impact Analysis

An attacker with access to a system using iSCSI storage (including virtualized environments via vhost-scsi) could trigger a kernel crash by sending specially crafted PR OUT commands. This causes denial of service (system reboot) and potential data corruption. Exploitation requires network access to the iSCSI target but no authentication.

Mitigation Strategies

Apply the Linux kernel patch that bounds PR-OUT TransportID parsing to the received buffer. Update to a kernel version containing the fix or backport the patch. If immediate patching is not possible, disable iSCSI target functionality or restrict access to iSCSI Target Port Groups (TPGs) until patched.

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