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 0612E45C70F for ; Fri, 11 Sep 2026 20:02:43 +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=1789156968; cv=none; b=IHGMK6HPptp08NdXgVYSa6LBRrFxkQrfqy4lIg7cxBc/cv/q9M9mCrExCdyqonkjKeTxpWbi/CIS6jSfFIkyhD/fuQA49XCRzKC0mnGf/qzSH1OvpgS73mAjZUfn6L9Rm5sdFzr5EzjgMAIf3pBYeZqTfrypMKxthsbT2cKHJDg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156968; c=relaxed/simple; bh=sL89uf3jJhfE/vyD+FUaditg+OLY9+WnpLE8s1WaDLc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Nk/kEu3r8waIPtmgpu0H6yqjeJEccIJUtFgy+n5Y+vh3DC4rEWOsdX6YFqbxNqUNMz4g/R5IQlWk2wbgJBifRlJLHhxCBp0by3e5c8jmu76LsJ0CujUlgPQrDZw592Ncw3qNOlAvuTvxQ5LdavhMUfADiUFnicfFkOT3mmqXGpo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LTKza3d9; 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="LTKza3d9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 576F81F000FF; Fri, 11 Sep 2026 20:02:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156960; bh=vbbX5ydMEfXYGsb3tkw3x6iwTv/Wxwt38ueQnfbaO+4=; h=From:To:Cc:Subject:Date:Reply-To; b=LTKza3d9AssdsQo7XKMlVCfU6EWxbBEEHcXGc+L6WYEo4T0h7ZRqdieK6p0fHDtnO RqB/zIXYCidPxJhOgHsitJFVp7hsfFspoJ6iB3gjzLsRMyk9HxoFTEmVilyyyEA/hT nyOPbHXuchM9ZuIgPDB8qe0fDMTsFGjhtVSznkdc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89690: nfsd: defer vfree of compound ops to fix rpc_status UAF Date: Fri, 11 Sep 2026 21:46:19 +0200 Message-ID: <2026091153-CVE-2026-89690-56bd@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=3308; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=rrN1kKOB37Tn+LxS1ddGCn4CCnGPxUq2bR2KIUWTkcU=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIht5oq5fNT8lnX/XlePzqZOap82+bxcz3Zb76f3Xk KagjbbOHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRTTMYFlwS3SNU7N8rbnf0 7VKJSatz/qXmHGJYcN1un7bou+OaPAxf322MT7bXXrdWBAA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: nfsd: defer vfree of compound ops to fix rpc_status UAF The rpc_status netlink dumpit walks every in-flight svc_rqst under rcu_read_lock and, for NFSv4 requests, reads opnums out of args->ops[]. But args->ops is a separate vmalloc buffer freed synchronously by vfree() in nfsd4_release_compoundargs() at the end of every compound. The dumpit's rcu_read_lock pins the svc_rqst struct itself (freed via kfree_rcu), but nothing defers the vfree of the ops buffer across the RCU grace period. A concurrent compound completion can therefore free the buffer while the dumpit is reading it — a use-after-free on vmalloc memory. The trailing seqcount recheck (smp_load_acquire of rq_status_counter) cannot undo a load that already retired against freed memory. Fix by replacing vfree(args->ops) with kvfree_rcu_mightsleep(), which defers the free until after an RCU grace period. This makes the existing rcu_read_lock in the dumpit sufficient to protect the read. The tradeoff is that completed compound ops buffers (up to 200 * sizeof(struct nfsd4_op)) persist in memory slightly longer, across one grace period, before being reclaimed. The Linux kernel CVE team has assigned CVE-2026-89690 to this issue. Affected and fixed versions =========================== Issue introduced in 6.7 with commit bd9d6a3efa9709e653aafbeb859289feccb8e70c and fixed in 6.12.109 with commit 48f72aff24f7a7329209dc6cbc27c869f3e3595c Issue introduced in 6.7 with commit bd9d6a3efa9709e653aafbeb859289feccb8e70c and fixed in 6.18.50 with commit 6703199f4d7e7f37d6a726a849eb358e8fae72fb Issue introduced in 6.7 with commit bd9d6a3efa9709e653aafbeb859289feccb8e70c and fixed in 7.2.4 with commit 19413ccc45070a7270b9e25c2a258daf7f91de42 Issue introduced in 6.7 with commit bd9d6a3efa9709e653aafbeb859289feccb8e70c and fixed in 7.3-rc1 with commit fca26a3fc19ed02278aa2a150af82d43db0302cb 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-2026-89690 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: fs/nfsd/nfs4xdr.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/48f72aff24f7a7329209dc6cbc27c869f3e3595c https://git.kernel.org/stable/c/6703199f4d7e7f37d6a726a849eb358e8fae72fb https://git.kernel.org/stable/c/19413ccc45070a7270b9e25c2a258daf7f91de42 https://git.kernel.org/stable/c/fca26a3fc19ed02278aa2a150af82d43db0302cb