mailbox: riscv-sbi-mpxy: validate RPMI notification lengths (CVE-2026-90191) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90191

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths

Answer in brief

CVE-2026-90191 records a Unknown severity vulnerability in mailbox: riscv-sbi-mpxy: validate RPMI notification lengths. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 <cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b \|\| >=bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 <c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76 \|\| >=bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 <11d5af151bcbe78f5a579e0faecd3be9cea0399a	cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b, c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76, 11d5af151bcbe78f5a579e0faecd3be9cea0399a
Linux/Linuxgeneric	6.18	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: mailbox: riscv-sbi-mpxy: validate RPMI notification lengths The SBI return value controls how many bytes are copied from shared memory into the RPMI notification buffer. It is not validated against the negotiated shared-memory size before that copy. The event walker also uses a reversed loop condition and can inspect a short event record. Validate the complete notification length before copying it, iterate only while a full event header remains, and stop when a declared event payload extends beyond the copied notification data.

Quoted source text, attributed separately from HOL analysis.