CVE-2026-72084

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 TransportIDs 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.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/004ccd2d3b4ac36a300e05e01df152e5c02a5a82
• https://git.kernel.org/stable/c/03fbc7de8d5e85fc8420e57e8304c855efd453ab
• https://git.kernel.org/stable/c/555a89846ed888d7401b3f7200934c0fbedcbb46
• https://git.kernel.org/stable/c/6ca5de8782e67573a61a6736b6dc0ffe58dcdf59
• https://git.kernel.org/stable/c/842248047ef28dbf3b3f7f49a0ec315054d4dab8
• https://git.kernel.org/stable/c/88c67c3de914e19172e1d878a7625c5b06c20ec5
• https://git.kernel.org/stable/c/9298078a8f7d8181a04614a34ab655ccdf038204
• https://git.kernel.org/stable/c/d04a179085c262c9ed577d0a4cbc6482ff1fd9a3