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 DC5BF5921F5 for ; Fri, 11 Sep 2026 20:06:16 +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=1789157179; cv=none; b=NGuMEXDIZArYEaSnUH0PnwimMT1EZpY2TDmm4oa7Ma6AQIiXUfnlTNkr9e9VDxEDYfFhgF1fbqvo+EoAI5Z21rOrFeOUcYuiUqE9WCNeOvfGfsLK+EcJxNO+WiI1PVw01DK8Lbw0SQRLWppj14MEUzb10sDcg0LNxraAE6lfuME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789157179; c=relaxed/simple; bh=l/K/lOdKrlcAskbqtxK6UaCBwkR1050NtnNl9BPzWPE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XXb8zTI4hn3H5QQnRj4bamTKUSDZteC826pc7CvmSgiaET6/Nc5vIwpbDwcrBBnyxVy7hq3XoAHOUoWyA2Mcv7vVMjOdR42ZHQxKSdwJp2y47UqNqelt+ulLfg9n729OniB3wNP269qS6awIMLXcPZjnU8Q55cQKjvOnsRihzi0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WlfxUXq6; 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="WlfxUXq6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49BE71F00893; Fri, 11 Sep 2026 20:06:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789157175; bh=DcYAA7iqVzOPCZq4eApVAWO9qdkuoKEB/dWCm0Z/UH8=; h=From:To:Cc:Subject:Date:Reply-To; b=WlfxUXq65kcujYRxePAVaEWH46d/U0VlKHAO4aqFkS47rGJazoBnpBMN/Fd8hjdb0 N6YlJFL50WoFW0+VOqb3bMeGGGVSFQo9WOKLRzxRrGawntuBleirjYENF4Udqgt45c qwbXxaNZiA6O68+/FpKkBbxEP0JJLSm5rcdVEP08= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89761: apparmor: fix out-of-bounds write when null terminating a label vec Date: Fri, 11 Sep 2026 21:47:30 +0200 Message-ID: <2026091109-CVE-2026-89761-b077@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=3891; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=663vPcrJpeww1FGAN32TOvEBzPlCZ4WnTUdJSVvBOck=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIie67etuv7xtjR3Ll+ctFxfnbCs+7bU+SkbJWlimf tH3ApNXHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARrz6GeUYvzjDeWlZjlWG0 aZ+x8kM+i8R/OxjmVx42kZPJS1XllCjbFWDucDXzSr4sAA== 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: apparmor: fix out-of-bounds write when null terminating a label vec aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE is passed. If the components are all distinct no duplicates are dropped, dups is 0 and the terminator goes to vec[n], so the caller has to provide room for n + 1 entries. aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len, gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it allocates exactly len pointers. The terminator therefore lands one entry past the end of the local array when len is LOCAL_VEC_ENTRIES, and one entry past the end of the allocation when len is larger. len comes from the number of "//&" separated components in the label name and label_count_strn_entries() does not bound it. An unprivileged task reaches the parse by writing to /proc/self/attr/apparmor/current or through lsm_set_self_attr(2), both of which go through do_setattr(), and the name is parsed before the change_profile permission is checked. The query_label() path behind the securityfs .access file, which is mode 0666, performs no permission check at all. Every component has to resolve to a loaded profile, so a system with policy loaded is required. The other two VEC_FLAG_TERMINATE users work on a label vec that aa_label_alloc() has already sized with "+ 1 for null terminator entry on vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of the local array and into kzalloc(). The Linux kernel CVE team has assigned CVE-2026-89761 to this issue. Affected and fixed versions =========================== Issue introduced in 4.13 with commit f1bd904175e8190ce14aedee37e207ab51fe3b30 and fixed in 6.12.109 with commit 9124e078ea2250d8d01d2162a550acb01ef5bf48 Issue introduced in 4.13 with commit f1bd904175e8190ce14aedee37e207ab51fe3b30 and fixed in 6.18.50 with commit 28069434aef66b9d084f0609b7a29c171846815e Issue introduced in 4.13 with commit f1bd904175e8190ce14aedee37e207ab51fe3b30 and fixed in 7.2.4 with commit 36bdd0b45ec3f4822832a56e9db8674c8450dfce Issue introduced in 4.13 with commit f1bd904175e8190ce14aedee37e207ab51fe3b30 and fixed in 7.3-rc1 with commit 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123 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-2026-89761 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: security/apparmor/include/label.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/9124e078ea2250d8d01d2162a550acb01ef5bf48 https://git.kernel.org/stable/c/28069434aef66b9d084f0609b7a29c171846815e https://git.kernel.org/stable/c/36bdd0b45ec3f4822832a56e9db8674c8450dfce https://git.kernel.org/stable/c/9f1e40193eef7f047e6b77cfb4b4cafdecd7a123