From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D18CF37B00F for ; Sun, 18 Oct 2026 15:34:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792337695; cv=none; b=d9uZNRux9oIMttBDDiwh9WQKaN2MFmv58q3Sj7xLLDKFG7TSP070hoekenoMTlbYZjcsr6+lPdCnz+qJdedPnQWdYDDXU6XuJFO2p20iC4WJ43CvTGEdVS/u28iMUtWpgsM4nzeqIm8m+36tnF4oWYn4eSgoYjhj0NLrgPXpRT0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792337695; c=relaxed/simple; bh=tVCQ7KwdLme7lu1H/r05YxeOViEBKbsT3m+AHCXpbR4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XLbjBfVQz1kiVD8szT00b0gvRIiUyZmmEaGQTWLBxnD9nydgJcce3ozhqojeB+dIspd+aV+3DS+dwIVdzw8Z8n+u2JYsddVpgiicVMovNOCsbnsb2IcuauLIPm+nwLlSzdhwEAldna3bvL7C6lv7Ic65aiyzMJJrGPMYJheX19c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EfQDH4+I; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EfQDH4+I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED0191F000C4; Sun, 18 Oct 2026 15:34:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792337694; bh=BWfQj1En9ZOSdverH2BLFghJtzbh427eOol6762c8ek=; h=From:To:Cc:Subject:Date:Reply-To; b=EfQDH4+I4Kjn1sh3m4ZUqKmrTxdcW94BtVCe6LJIHIXAEM9woHEPQbb/zNckLA38I oLNB1MEKy6SyCaqENQZSujz6JuLgkVktX9qqVy8xOQQ1qYC/wGj9Xi11JqsZ1f3MAH A0XxmQ2BlUp4dhQ5tBpdpcaSgFjO2CmzbNxp41Rc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-98581: nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm() Date: Sun, 18 Oct 2026 17:17:25 +0200 Message-ID: <2026101834-CVE-2026-98581-ecae@gregkh> X-Mailer: git-send-email 2.56.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5183; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=8Wg9uNUZ5byo4/nh8KZjM8+nUT27pBqgtsqBOkxYDHg=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlXHk2bEXJbN3ynx5bpkyeavHJhe/0wyvY6V5RytoIkP /eqNP9dHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARN3+G+SU1B9bNXP4gaXpO cVGIgsrdiew92gwL9h9Kifh+tPinFUNqTF2F7z+/FI16AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm() nfc_llcp_recv_dm() handles DM(NOBOUND)/DM(REJ) for a socket that is still linked on local->connecting_sockets: it looks the socket up with nfc_llcp_connecting_sock_get(), sets sk->sk_state = LLCP_CLOSED and returns, without taking the socket lock and without unlinking the socket from the connecting_sockets list. llcp_sock_release() selects the list to unlink from by sk_state: a socket in LLCP_CONNECTING is unlinked from connecting_sockets, otherwise from the sockets list. Because recv_dm left the socket physically on connecting_sockets but in the LLCP_CLOSED state, release() takes the else branch and calls nfc_llcp_sock_unlink(&local->sockets, sk). That runs sk_del_node_init() while holding sockets.lock, i.e. it removes the socket from the connecting_sockets hlist under the wrong lock. A concurrent connect() linking another socket onto connecting_sockets under connecting_sockets.lock then mutates the same hlist unserialized, which corrupts the list and desyncs the sk_add_node()/sk_del_node_init() sock_hold()/__sock_put() pairing. An unprivileged local process holding LLCP sockets, with the DM supplied by the remote peer over an established LLCP link, can drive this to leak kernel sockets without bound (the mis-decrement goes through the non-freeing __sock_put() path, so the object is never released), leading to memory exhaustion / DoS. This is the same class of bug that was fixed in the sibling handler nfc_llcp_recv_cc() by commit b493ea2765cc ("nfc: llcp: Fix use-after-free race in nfc_llcp_recv_cc()"); recv_dm did not receive the equivalent fix. Fix it the same way: take lock_sock(), re-check that the socket is still hashed (release() may have won the race), and for the NOBOUND/REJ case unlink it from connecting_sockets before moving it to LLCP_CLOSED. The unlink drops the connecting_sockets membership reference via sk_del_node_init(), leaving the socket unhashed, so the later nfc_llcp_sock_unlink() in llcp_sock_release() becomes a no-op and no double put occurs. The Linux kernel CVE team has assigned CVE-2026-98581 to this issue. Affected and fixed versions =========================== Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 5.10.271 with commit dd2d24add86b3b63cd87cf2feff98ae119ba19a6 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 5.15.222 with commit 812731dd8511f5768f4ff279b3c18d85cd21da4b Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 6.1.189 with commit dba1d9c7134afcb4b1bfad8c1b1b3f0ab5189b08 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 6.6.158 with commit c1e9ed52a6697354366dddf190fbacee8ed2f7c5 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 6.12.112 with commit 7fb2c0eeb79bfad64065f539a453138abd0edda6 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 6.18.55 with commit b94cf09720543cc34256c7aa88f8059cbe7c0419 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 7.2.9 with commit 320a2ff49bdce3f9a437b9a9ff341ff27d3bdbf1 Issue introduced in 3.6 with commit a69f32af86e389dd232b1bb2269e202c1bfcc60f and fixed in 7.3-rc5 with commit bf1460acdf8cf5a07c819f59785d40f20d113099 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-2026-98581 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/nfc/llcp_core.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/dd2d24add86b3b63cd87cf2feff98ae119ba19a6 https://git.kernel.org/stable/c/812731dd8511f5768f4ff279b3c18d85cd21da4b https://git.kernel.org/stable/c/dba1d9c7134afcb4b1bfad8c1b1b3f0ab5189b08 https://git.kernel.org/stable/c/c1e9ed52a6697354366dddf190fbacee8ed2f7c5 https://git.kernel.org/stable/c/7fb2c0eeb79bfad64065f539a453138abd0edda6 https://git.kernel.org/stable/c/b94cf09720543cc34256c7aa88f8059cbe7c0419 https://git.kernel.org/stable/c/320a2ff49bdce3f9a437b9a9ff341ff27d3bdbf1 https://git.kernel.org/stable/c/bf1460acdf8cf5a07c819f59785d40f20d113099