Bug 2559783 (CVE-2026-99026)

Summary:	CVE-2026-99026 kernel: net: team: free skb when broadcast has no txable port
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
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 Linux kernel's team network driver. When a team interface is configured in broadcast mode and lacks transmittable ports, the driver fails to properly free packet buffers during transmission. A local user can exploit this vulnerability by sending network traffic through the interface, leading to socket memory exhaustion and a Denial of Service (DoS).	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 2026-10-23 13:37:00 UTC

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

net: team: free skb when broadcast has no txable port

bc_transmit() sends the original skb through the last txable port.
When no port is txable, it returns false without consuming the skb, but
team_xmit() still returns NETDEV_TX_OK. AF_PACKET sends then retain the
skb and its socket write-memory charge.

A TX-enabled, link-down port keeps the broadcast transmit op installed.
Carrier can stay up through a second link-up, TX-disabled port or be
forced on by userspace. Free the original skb on the no-port path while
leaving the existing drop accounting intact.

Discovered by Sashiko during review of previous commit.

Comment 1 gkamathe 2026-10-27 11:14:14 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99026.mbox