Bug 2528588 (CVE-2026-80791)

Summary:	CVE-2026-80791 kernel: nvmet-auth: zero the AUTH_RECEIVE response buffer
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 Linux kernel's nvmet-auth subsystem. During the pre-authentication handshake, a remote attacker can exploit an issue where the system allocates a response buffer but only partially initializes it. The uninitialized portion of this buffer is then transmitted to the remote initiator. This can lead to the disclosure of sensitive information from kernel memory.	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 2026-09-04 15:37:08 UTC

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

nvmet-auth: zero the AUTH_RECEIVE response buffer

nvmet_execute_auth_receive() allocates the response buffer with kmalloc()
sized by the host-supplied AUTH_RECEIVE allocation length, but the
DH-HMAC-CHAP builders write only a fixed-size message into it. The full
allocation length is then copied to the wire by nvmet_copy_to_sgl(), so a
remote initiator receives the bytes past the built message -- up to nearly
a page of uninitialized slab -- during the pre-authentication handshake.

Allocate the buffer with kzalloc() so the unwritten tail is zeroed before
it is sent; conforming responses are unaffected.

Comment 1 gkamathe 2026-09-08 10:14:13 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80791.mbox