Bug 2536155 (CVE-2026-90392)

Summary:	CVE-2026-90392 kernel: bpf: Fix potential UAF when reading bpf link info
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
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 BPF (Berkeley Packet Filter) subsystem. A local attacker could exploit a Use-After-Free (UAF) vulnerability by concurrently replacing a BPF program while its information is being read without proper locking. This could allow the attacker to achieve privilege escalation or cause 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 16:40:58 UTC

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

bpf: Fix potential UAF when reading bpf link info

In bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is
accessed without holding any locks. If the prog is concurrently replaced
via bpf_link_update, the old prog can be freed, leading to a potential
UAF issue.

Fix this by accessing link->prog under RCU protection to safely fetch
the pointer and guarantee its lifetime while reading its fields.

Comment 1 gkamathe 2026-09-21 08:29:23 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90392.mbox