CVE-2026-52970: netfilter: nft_ct: fix missing expect put in obj eval

CVE-2026-52970: netfilter: nft_ct: fix missing expect put in obj eval

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

netfilter: nft_ct: fix missing expect put in obj eval

nft_ct_expect_obj_eval() allocates an expectation and may call
nf_ct_expect_related(), but never drops its local reference.

Add nf_ct_expect_put(exp) before return to balance allocation.

The Linux kernel CVE team has assigned CVE-2026-52970 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 5.10.258 with commit cdb9a25dd3416d427e8b2753210f8baf44207577
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 5.15.209 with commit 26ab32ec73941871c97562ee1f39587950dc3b68
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 6.1.175 with commit 7b96242ceedfe249f158419f3254bcee04173ffe
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 6.6.141 with commit ecca618e1e339494911090474ed87742c0f73976
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 6.12.91 with commit 2aef1b13d5c0285f340512c6c07eb858fd018fd8
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 6.18.33 with commit 1dced0725e2fae3ac3416274db20a7ff5a46931d
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 7.0.10 with commit 84c422cea5a45fe56be839f25880f21fd33940cd
	Issue introduced in 5.3 with commit 857b46027d6f91150797295752581b7155b9d0e1 and fixed in 7.1 with commit 19f94b6fee75b3ef7fbc06f3745b9a771a8a19a4

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-52970
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/netfilter/nft_ct.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/cdb9a25dd3416d427e8b2753210f8baf44207577
	https://git.kernel.org/stable/c/26ab32ec73941871c97562ee1f39587950dc3b68
	https://git.kernel.org/stable/c/7b96242ceedfe249f158419f3254bcee04173ffe
	https://git.kernel.org/stable/c/ecca618e1e339494911090474ed87742c0f73976
	https://git.kernel.org/stable/c/2aef1b13d5c0285f340512c6c07eb858fd018fd8
	https://git.kernel.org/stable/c/1dced0725e2fae3ac3416274db20a7ff5a46931d
	https://git.kernel.org/stable/c/84c422cea5a45fe56be839f25880f21fd33940cd
	https://git.kernel.org/stable/c/19f94b6fee75b3ef7fbc06f3745b9a771a8a19a4