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 82E29583AB5 for ; Fri, 11 Sep 2026 19:58:14 +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=1789156699; cv=none; b=Vg09sejcryt99HTY30ft++tOguPEZ2YD0bbfvEnqLMXgwwrDbpH7Dxu0xUQSpmaIhIZb3C+Qrp7Xs1ozjCAmAKeB+2ZpTfE3VWXkfN2jIah1VvYiIqA5XQFK8niV5FG8thx6Yt3cOsIrTdz5r2u/IgE2VheIjItWnrJZ2dyprDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156699; c=relaxed/simple; bh=qQ3F1R5mq31XxG7RK88XFWTYxMmSOe5oZ0DRUb+qMYM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=DYUBRmSZJHZt76oyr5JtwVVm6SQHSFRNvI7ppmCQngWFR3PIidZBz5PuuDWNA+cGDFgIdDCqMpugSEXWjzpyYE1CIYctUIzwMcP8fPcm3qMlsDPOxCuOU7E/77R+DNiixFl74HABTElNKTkkp53H50Ium7/uwJKbK0iM58Py0vI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sDXEs4SF; 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="sDXEs4SF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36DCA1F0089A; Fri, 11 Sep 2026 19:58:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156693; bh=mmYysyzn0yrsk9BuM/PmAR/S+ME5iDZHNHxvEp7nwmc=; h=From:To:Cc:Subject:Date:Reply-To; b=sDXEs4SFZ7slOdKue8GgKPxobJblqkAmdIq9DWfmMFHZ4m8xhjTnELEuKJpezYZdw bpHHJBPtTNKtnCqkfeBIHESGP9HEKR0u49CqN372GH3WKuDAWcWUk/czuBSFDNWe92 pWnSQpQC3gXhdJL9Urmpn/nTiq8Nrsr0WtuM8R74= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89603: entry: Fix seccomp bypass after ptrace with TSYNC Date: Fri, 11 Sep 2026 21:44:52 +0200 Message-ID: <2026091133-CVE-2026-89603-dad5@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=2980; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=YIGo+SkIf2yGzvEqdCfHRuRPCDnW6dsSD7sCbNbmaUk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLInMf/NB/FrbgbyJLbP56wf6Xy0ojD81OXckY6P7g4 YLHYqcFO2JZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiN98wLNj8cWXG86h/hZp7 7TK/9Gw3VtT0dmRY0N5581fabIv1Z9MXXr+4q9F00t40ZgA= 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: entry: Fix seccomp bypass after ptrace with TSYNC Sashiko review pointed out the following issue. If a thread is stopped in syscall_trace_enter() for ptrace, another thread can install a seccomp filter with SECCOMP_FILTER_FLAG_TSYNC (e.g., via seccomp_attach_filter()). This will successfully set SYSCALL_WORK_SECCOMP on the stopped thread, but syscall_trace_enter() evaluates a cached 'work' variable sampled on entry. Consequently, the subsequent check for SYSCALL_WORK_SECCOMP misses the newly assigned flag, and the filter is silently bypassed. This race condition could allow an unprivileged process to execute a prohibited system call (e.g., execve) that the newly installed filter was intended to block, especially since the tracer might have modified the system call number during the ptrace stop. Fix this by re-reading the syscall_work flags after ptrace handling, so that any new SYSCALL_WORK_SECCOMP flag set by another thread via TSYNC during the ptrace stop is observed before the subsequent seccomp check. The Linux kernel CVE team has assigned CVE-2026-89603 to this issue. Affected and fixed versions =========================== Issue introduced in 5.9 with commit 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 and fixed in 6.18.51 with commit 459f33f82864723a7fa366cf1091d9c6c893b6b2 Issue introduced in 5.9 with commit 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 and fixed in 7.2.4 with commit ab4647459098a43e9d6fdb860836f08c962f3774 Issue introduced in 5.9 with commit 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 and fixed in 7.3-rc1 with commit 4a3591287fb7f808e209b4974ed337f609a2006b 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-2026-89603 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: include/linux/entry-common.h 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/459f33f82864723a7fa366cf1091d9c6c893b6b2 https://git.kernel.org/stable/c/ab4647459098a43e9d6fdb860836f08c962f3774 https://git.kernel.org/stable/c/4a3591287fb7f808e209b4974ed337f609a2006b