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 20EEA5867E5 for ; Fri, 11 Sep 2026 19:55:24 +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=1789156527; cv=none; b=Dxv3HxNmOKQCUB2cgRYjLayG+OqrbOg+0qUNyHptSsqB0koxViedXE1fLdErefMN3+p/WuY/niKw9e7XXKXu92l3aEJegGitAKVPtKoPRyWU82uOFcTV+TEJGYB5SCZW3U/YQ3AAKahLL3mgNaKgIDBZsI+6ael+GPndEqjimVM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156527; c=relaxed/simple; bh=OZiCgdsnA1lLaokh+gxyUN7Vq5kXlMQoNDk1WGPUtXA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=hyhzXrx5C2SnmaauhzcJDARAuWakxGNwxS7QdZgIJaA8zfrJ+9QQ61J3sqnCwZgLLsrX+eSCGzmNf6TgfssRYZ485SZGqGpWz3A7vnO9kIDJkU/Y2KUi0a0ZZfOaLAsABkj9MBnWagwNYQXBvZ4GZCqoXbd/A8ZdDzNP5wdiICE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2Sde4Pna; 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="2Sde4Pna" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3C981F00898; Fri, 11 Sep 2026 19:55:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156523; bh=dFN7ltq/Gp5/+g7JFVWQj+5aHKVmKEamh5fNPPwNz08=; h=From:To:Cc:Subject:Date:Reply-To; b=2Sde4Pna0djIRw34gm0SVqWDQW3VlPWHA7I/9sjug9p71qh56nJ4BbTuG5pIaYR9p 27OXmRAWaV5r3N60Mf1os/QXW7VzJM8rlj254rJybAs0+8PzBz/RpdRyMnFr0UujR5 xKBe+tO0QO05KIp2l8UlGuc/XdDohd/QEClE5HDo= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89544: SUNRPC: fix gssx_dec_option_array error path bugs Date: Fri, 11 Sep 2026 21:43:53 +0200 Message-ID: <2026091120-CVE-2026-89544-dc47@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=5277; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=woXpDVxWkcTg3giAEz3NQkXCVhlF3CAFBDjCLqpPRD0=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIhPOXu17fdSz6b5ha6PAr4LpnJYi79S/ca5RV2vfe VfhSsvXjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIlWCGBf1sl9d4d1zK7c5k /XjDzVY377TNVob57rdmntVWOqyVX592/IE9X0ZHZ/oeAA== 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: SUNRPC: fix gssx_dec_option_array error path bugs Four coupled defects in the gssx XDR option-array decoder make the error paths unsafe: a NULL deref in the caller, a refcount leak on the decoded group_info, and a latent use-after-free that the leak fix would otherwise expose. gssx_dec_option_array() sets oa->count = 1 before allocating oa->data. If that allocation fails, -ENOMEM is returned with oa->count == 1 and oa->data == NULL. All other error paths jump to free_oa: which frees oa->data and NULLs it but also leaves oa->count == 1. The caller trusts the count: gssp_accept_sec_context_upcall() gssx_dec_accept_sec_context() gssx_dec_option_array() /* fails, count=1 data=NULL */ data = res.options.data[0].value /* NULL deref */ Independently, free_creds: releases the partially decoded svc_cred with a bare kfree(creds). gssx_dec_linux_creds() installs a groups_alloc() result into creds->cr_group_info; that object is kvmalloc-backed and refcounted, and only put_group_info() reaches kvfree(). A plain kfree(creds) drops the wrapper and leaks the group_info allocation. The natural fix for the leak is to call free_svc_cred(creds) before kfree(creds), but free_svc_cred() invokes put_group_info() on creds->cr_group_info unconditionally when non-NULL. The existing out_free_groups: path in gssx_dec_linux_creds() already called groups_free() on that pointer without clearing it, so once free_svc_cred() is wired in, the subsequent put_group_info() would touch freed memory. Fix all four together: - Move the oa->count = 1 assignment below the oa->data allocation so it is never set when oa->data is NULL. - Reset oa->count to 0 at free_oa: so count and data stay coherent and the caller sees an empty option array. - Call free_svc_cred(creds) before kfree(creds) at free_creds: so the refcounted cr_group_info is released. free_svc_cred() either NULL-guards each field explicitly (cr_group_info has an if() check) or delegates to a helper that is NULL-safe itself (kfree for the string fields, gss_mech_put() which guards with if(gm) at gss_mech_switch.c:342), so it is safe to call on a partially decoded svc_cred where only cr_uid/cr_gid/cr_group_info have been written and everything else is zero from kzalloc. - In gssx_dec_linux_creds()'s out_free_groups: path, release cr_group_info with put_group_info() rather than groups_free() so the teardown matches free_svc_cred()'s refcount-aware path, and clear the pointer so a later free_svc_cred() on the same creds does not release it a second time. The Linux kernel CVE team has assigned CVE-2026-89544 to this issue. Affected and fixed versions =========================== Issue introduced in 6.9 with commit 3cfcfc102a5e57b021b786a755a38935e357797d and fixed in 6.18.51 with commit 3ff45361e9469e85c0f86b8e7b82c63e50bab8ef Issue introduced in 6.9 with commit 3cfcfc102a5e57b021b786a755a38935e357797d and fixed in 7.2.4 with commit f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a Issue introduced in 6.9 with commit 3cfcfc102a5e57b021b786a755a38935e357797d and fixed in 7.3-rc1 with commit 5e9a94539b1ec17a89177d952badfd0d844d694a Issue introduced in 4.19.311 with commit b97c37978ca825557d331c9012e0c1ddc0e42364 Issue introduced in 5.4.273 with commit bfa9d86d39a0fe4685f90c3529aa9bd62a9d97a8 Issue introduced in 5.10.214 with commit bb336cd8d5ecb69c430ebe3e7bcff68471d93fa8 Issue introduced in 5.15.153 with commit dd292e884c649f9b1c18af0ec75ca90b390cd044 Issue introduced in 6.1.83 with commit 934212a623cbab851848b6de377eb476718c3e4c Issue introduced in 6.6.23 with commit 5e6013ae2c8d420faea553d363935f65badd32c3 Issue introduced in 6.7.11 with commit 9806c2393cd2ab0a8e7bb9ffae02ce20e3112ec4 Issue introduced in 6.8.2 with commit 996997d1fb2126feda550d6adcedcbd94911fc69 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-2026-89544 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/sunrpc/auth_gss/gss_rpc_xdr.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/3ff45361e9469e85c0f86b8e7b82c63e50bab8ef https://git.kernel.org/stable/c/f85a83774d7f4e2ac71c0c384df0dfb6f7d0179a https://git.kernel.org/stable/c/5e9a94539b1ec17a89177d952badfd0d844d694a