Bug 2540522 (CVE-2026-93824)

Summary:	CVE-2026-93824 kernel: tls: reject the combination of TLS and sockmap
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 Transport Layer Security (TLS) subsystem. A local user can trigger this vulnerability by configuring TLS keys on a network socket already attached to a Berkeley Packet Filter (BPF) socket map (sockmap). This unsupported integration exposes latent flaws in the networking stack, potentially resulting in memory corruption and a denial of service (DoS).	Story Points:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-24 17:06:35 UTC

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

tls: reject the combination of TLS and sockmap

TLS and sockmap (BPF psock) integration hides a lot of latent bugs.
Bugs which may be more or less relevant for real users but they
are definitely exploitable.

We could not find anyone actively using this integration so let's
reject this config. Adding a TLS socket to a sockmap was already
rejected by sk_psock_init() through the inet_csk_has_ulp() check.
We need to reject the attempts to configure the TLS keys (rather
than adding the ULP itself) because checking prior to the ULP
installation is tricky without risking a race with sockmap getting
added in parallel (sockmap does not hold the socket lock).

This patch is a minimal rejection of the feature. Subsequent patch
in the series will do a light dead code removal. Full cleanup would
require a major rewrite of the Tx path, we don't need skmsg any more.

Comment 1 Mauro Matteo Cascella 2026-09-28 15:28:05 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93824.mbox