scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write resp_report_zones() sizes the reply buffer from the CDB allocation length. The v3 fix rounds alloc_len up with ALIGN() before deriving the descriptor count: rep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) - RZONES_DESC_HD) >> ilog2(RZONES_DESC_HD); arr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1); For alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to 0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()'s size_t is 32-bit and truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which passes the !arr check, and desc = arr + 64 is then dereferenced in the loop -> out-of-bounds write / panic. Clamp rep_max_zones to devip->nr_zones. The loop already stops at sdebug_capacity (after nr_zones zones), so a report can never hold more than nr_zones descriptors; the clamp does not change the report, it only bounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device property that can never reach 0x100000000.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.15.217, 5.11
- Fix · CNA Linux (Linux) Fixed in 5.15.217, 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74470
- 2026-10-03 Alias added: GHSA-jmr9-wc6r-pj32
- 2026-10-18 CISA SSVC decision points changed
References
Other 7
- https://git.kernel.org/stable/c/7b615fc139e35c81077046df44725c532f7e2404
- https://git.kernel.org/stable/c/5d3e1d006bbb543259f9e31824caadbfff6a5465
- https://git.kernel.org/stable/c/49e5b25a0b74dbac595f122e5608fdce2918cc4e
- https://git.kernel.org/stable/c/495058429ca55ab7fcc21977b63b92907ad68066
- https://git.kernel.org/stable/c/2047ed09bf13453b7d6f9431b112ec07984dd69b
- https://git.kernel.org/stable/c/d6e6da6bc3b53231fac77ffab428da8173ee729c
- https://git.kernel.org/stable/c/93dde0bf2f39a0f9f57fd610aa3201ce5b753433
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Sources
- CVE-2026-74470 · CVE Program
- CVE-2026-74470 · NVD
- FIRST EPSS
- GHSA-jmr9-wc6r-pj32 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74470 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences