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 99711572696 for ; Fri, 11 Sep 2026 19:52:55 +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=1789156391; cv=none; b=TTM++H2k2MsmBVVDtACgkCXKcSCjibqa8vd2VRe0NMCZdZ0xsCjsazShDrJo5yme8ltwV8VwBjyxPdJHChBxTrEvdELA01vK+rV1e0xuUYdIwsCX/XeWOPlbkJCPvmnUrDzSCqtc2ykMaJ7eqH2beMKJfO5RaIO4VFl8fLolj7I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156391; c=relaxed/simple; bh=gWIXfKA4El4wuRFr0kRqlu4oDpXlOuY9s3ifLjXwt58=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=oTcczhz1yvvfOYcPB3cd5TVRhMxK9uVVPUh6NvUZ+84vjsgdKQItliBDxfn1+I1bbbCjmM00Y7VFfeyEDtGf0Yz2E/65jYqi7ctZ7dx86btkScC0iKz8W4e8CKlggPNm1iXgQMkK9qNgFfVYV1qOpsb3tS8w7Chf7HxsXUqKTps= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gm0Ozl8K; 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="gm0Ozl8K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1AEF1F00898; Fri, 11 Sep 2026 19:52:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156372; bh=Eeygn8X2NpqfoAHw3bDDDiGFPFpAIw6wbV4unIOltnI=; h=From:To:Cc:Subject:Date:Reply-To; b=gm0Ozl8KTAeRPAK/lsqlz40tIZ9vLKWTJY7/j/QRIap+Cjs/a1TZvg0o186d+6Krt KILZpqqsCz/ewMc/6/OTn/KuQsOot0fm4fbKtGn5+twVCzW6uip5iwyPmgG4wAyL52 mBf036ZRHppAErc7mIgsabVx2B1xp8HC+G/q+9cs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89478: sctp: drop a chunk if its transport was removed Date: Fri, 11 Sep 2026 21:42:47 +0200 Message-ID: <2026091104-CVE-2026-89478-5961@gregkh> X-Mailer: git-send-email 2.55.0 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=3309; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=IrO28w8wLqJQTMCcDlpsPCeGWaMB3c9LBLlEhGPRIdo=; b=kA0DAAIRMUfUDdst+ykByyZiAGqkWVGhC7EWZAXkU/jXD2nJrEgHCBBrrjOrxuYeI/1bOKOCK ohdBAARAgAdFiEE9LYMxb94wiFKMT3LMUfUDdst+ykFAmqkWVEACgkQMUfUDdst+ymQNwCeOs+d L0dZzKEZL737WkUbeJk1iLoAoMPb2iHVyu6PmaeVBo9M3veOkFi6 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: sctp: drop a chunk if its transport was removed sctp_rcv() resolves the transport once per packet and leaves it in chunk->transport. The lookup reference, or the one sctp_add_backlog() takes if the socket is owned by userspace, keeps it around until the chunk has been processed. An authenticated ASCONF DEL-IP can remove it in the meantime. sctp_assoc_rm_peer() takes the transport out of the association and calls sctp_transport_free(), which tags it dead and drops the reference the association held. There is a window on both paths: the packet can sit on the socket backlog, and on the direct path the lookup completes before bh_lock_sock(). The DATA chunk in that packet puts the removed transport back into asoc->peer.last_data_from. Once the packet is done that reference goes away and the transport is freed by RCU, so the next delayed SACK carries the pointer into the SACK chunk and sctp_outq_select_transport() reads the freed transport's state. Drop the chunk in sctp_inq_push(), next to the existing rcvr->dead check. Both paths reach it with the association's socket lock held. The peer retransmits it. The Linux kernel CVE team has assigned CVE-2026-89478 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.109 with commit c6c86a5e62a4fec36692ddd64b9144b660f71f96 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.50 with commit 1035bdef1efb9b1076d1a57b81e08c637ff08ecc Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.2.4 with commit 3537961df2163258bddc230db0e18dc14e925ea6 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.3-rc1 with commit 03a9d10ecf71f54b2af8020935f2033d4a132be5 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-2026-89478 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/sctp/inqueue.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/c6c86a5e62a4fec36692ddd64b9144b660f71f96 https://git.kernel.org/stable/c/1035bdef1efb9b1076d1a57b81e08c637ff08ecc https://git.kernel.org/stable/c/3537961df2163258bddc230db0e18dc14e925ea6 https://git.kernel.org/stable/c/03a9d10ecf71f54b2af8020935f2033d4a132be5