Buffer overflow in Linux kernel UFS ARPMB replies
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 7 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 6.3 allocates a 96-byte reply buffer for bsg-lib requests, but UFS ARPMB replies need 104 bytes. When an Advanced RPMB command returns an extra header, the kernel writes 8 bytes past the end of the buffer.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: scsi: bsg: Pass reply_len to bsg_setup_queue() to fit UFS ARPMB replies bsg-lib allocates a 96-byte (SCSI_SENSE_BUFFERSIZE) reply buffer per job, but struct ufs_rpmb_reply is 104 bytes: a 40-byte struct ufs_bsg_reply followed by a 64-byte EHS. When an Advanced RPMB command returns an EHS, ufshcd_advanced_rpmb_req_handler() copies it right after the 40-byte header and writes 8 bytes past the end of the buffer. Let each BSG transport pass its reply buffer size to bsg_setup_queue() and have ufs_bsg request sizeof(struct ufs_rpmb_reply), so the full reply reaches user space. Other transports keep SCSI_SENSE_BUFFERSIZE.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to 6.6.161, 6.12.115, 6.18.59, 7.2.13 or 7.3, which contain the fix. Red Hat lists Red Hat Enterprise Linux 6 as affected with no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 6.6.161, 6.12.115, 6.18.59, 7.2.13, 7.3
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 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-28 Threatist record created from CVE-2026-99157
- 2026-10-28 Alias added: GHSA-m9gv-84j2-4jhf
- 2026-10-30 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@913a1876fbe9a168030013b9e6cb2746fe41fff4 +1 · CNA
- 2026-10-30 2 new references · CNA
- 2026-11-01 Affected versions changed · Red Hat
- 2026-11-01 CVSS score added · Red Hat
- 2026-11-02 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/913a1876fbe9a168030013b9e6cb2746fe41fff4
- https://git.kernel.org/stable/c/bfb0582708b3432919a8baaa3a65de5fdb1490ea
- https://git.kernel.org/stable/c/2effbe746452c108188f85a6951f2b0b65653840
- https://git.kernel.org/stable/c/7a755f6d47b811d3abd93c1642ce5e63894540b8
- https://git.kernel.org/stable/c/ec6b083915e8146e147314a5f4f1285d07b57bfc
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Sources
- CVE-2026-99157 · CVE Program
- CVE-2026-99157 · NVD
- FIRST EPSS
- GHSA-m9gv-84j2-4jhf · GitHub Advisory Database · CC BY 4.0
- CVE-2026-99157 · Red Hat security data · CC BY 4.0
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