Bug 2536409 (CVE-2026-90082)

Summary:	CVE-2026-90082 kernel: net: mana: Cap MSI-X vectors to the device MSI-X table size
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the `mana` network driver within the Linux kernel. This vulnerability occurs because the driver incorrectly calculates the number of Message Signaled Interrupts (MSI-X) vectors, leading to an out-of-bounds write. A local attacker, by operating a specially crafted virtual machine, could trigger a system crash, resulting in a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 17:45:02 UTC

In the Linux kernel, the following vulnerability has been resolved:

net: mana: Cap MSI-X vectors to the device MSI-X table size

mana_gd_query_max_resources() sizes gc->num_msix_usable from resp.max_msix
and the CPU count, but never from the device MSI-X table. On a 1792 vCPU
M-series VM that yields 1793 while the table has 1024 entries, and
mana_gd_setup_remaining_irqs() then walks indices 1..1792, running off the
end of the region mapped by msix_map_region():

  BUG: unable to handle page fault for address: ff8e347f8b99800c
  RIP: 0010:msix_prepare_msi_desc+0x7a/0x90
  RAX: 0000000000004000 RBX: ff4330cb164ea780 RCX: ff8e347f8b998000
  Call Trace:
   <TASK>
   __msi_domain_alloc_irqs+0x13a/0x440
   msi_domain_alloc_irq_at+0x149/0x1b0
   mana_gd_setup+0x351/0x890
   mana_gd_probe+0x274/0x390
   </TASK>

RAX is index 1024 * PCI_MSIX_ENTRY_SIZE, one entry past the table.

msi_insert_desc() does range check the index, but only against the MSI
domain hwsize, which matches the table only for devices on an MSI parent
domain. With a global PCI/MSI domain hwsize is MSI_XA_DOMAIN_SIZE, so
nothing bounds the request.

Cap num_msix_usable with pci_msix_vec_count().

Comment 1 Keith Grant 2026-09-22 18:48:57 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90082.mbox