In the Linux kernel, the following vulnerability has been resolved: PCI: dwc: ep: Flush cached MSI write before unmapping the iATU The MSI-X path… (CVE-2026-90332)
A vulnerability in the Linux kernel PCI driver for dwc endpoints was resolved that involved improper flushing of cached MSI writes before unmapping the iATU. The MSI path did not flush posted MSI writes before unmapping, potentially causing dropped or misrouted writes. The fix involves a readback operation to drain posted writes before unmapping. This vulnerability has a high severity score of 8.2 and affects the integrity and availability of the system.
AI Analysis
Technical Summary
The Linux kernel PCI driver for dwc endpoints had a flaw where the MSI path did not flush cached MSI writes before unmapping the iATU, unlike the MSI-X path which already performed this flush. This could lead to posted MSI writes being dropped or misrouted when the iATU entry is unmapped and reprogrammed. The fix introduced a readback from the mapped MSI window before unmapping to drain any posted MSI writes, ensuring proper delivery to the Root Complex. This resolves the issue by aligning the MSI path behavior with the MSI-X path.
Potential Impact
The vulnerability can cause integrity loss and availability issues due to dropped or misrouted MSI writes in the PCI endpoint driver. This could disrupt interrupt signaling and potentially impact system stability or operation. The CVSS score of 8.2 reflects a high severity with network attack vector, low attack complexity, no privileges required, no user interaction, and scope change.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to address this issue by adding a readback operation to flush posted MSI writes before unmapping the iATU. Users should apply the updated Linux kernel version containing this patch to remediate the vulnerability. No additional mitigation steps are indicated.
In the Linux kernel, the following vulnerability has been resolved: PCI: dwc: ep: Flush cached MSI write before unmapping the iATU The MSI-X path… (CVE-2026-90332)
Description
A vulnerability in the Linux kernel PCI driver for dwc endpoints was resolved that involved improper flushing of cached MSI writes before unmapping the iATU. The MSI path did not flush posted MSI writes before unmapping, potentially causing dropped or misrouted writes. The fix involves a readback operation to drain posted writes before unmapping. This vulnerability has a high severity score of 8.2 and affects the integrity and availability of the system.
CVSS v3.1
Score 8.2high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel PCI driver for dwc endpoints had a flaw where the MSI path did not flush cached MSI writes before unmapping the iATU, unlike the MSI-X path which already performed this flush. This could lead to posted MSI writes being dropped or misrouted when the iATU entry is unmapped and reprogrammed. The fix introduced a readback from the mapped MSI window before unmapping to drain any posted MSI writes, ensuring proper delivery to the Root Complex. This resolves the issue by aligning the MSI path behavior with the MSI-X path.
Potential Impact
The vulnerability can cause integrity loss and availability issues due to dropped or misrouted MSI writes in the PCI endpoint driver. This could disrupt interrupt signaling and potentially impact system stability or operation. The CVSS score of 8.2 reflects a high severity with network attack vector, low attack complexity, no privileges required, no user interaction, and scope change.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to address this issue by adding a readback operation to flush posted MSI writes before unmapping the iATU. Users should apply the updated Linux kernel version containing this patch to remediate the vulnerability. No additional mitigation steps are indicated.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-4589-rc6p-3w23
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-90332"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6aade51e55bf5e2cf5edc165
Added to database: 09/19/2026, 01:27:58 UTC
Last enriched: 09/19/2026, 01:48:08 UTC
Last updated: 09/19/2026, 04:01:42 UTC
Views: 2
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