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 CDA093126B9 for ; Wed, 24 Jun 2026 16:33:55 +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=1782318836; cv=none; b=ALmC+fIC+h9agMpcPFZ9l4G8ez4NBsxtujUJY9b2zC7qmZb68eKmYG2EUoEsTio/uOPtbm+N1ad/tJNy7nE1e7EUJZRZcaae4AgCg7bY+RxJtCU0JD/JupthrQSPNVOzpZPC1f+Lg0gFMeiCg5HF0zgU2uV9Le0qHBwIYsRIJJo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782318836; c=relaxed/simple; bh=kMUiQJRheSNiBt1X5ephUNWNktSCF8Fn6IBSxZRJLuo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=N8Lq6LS01+TRrpHfi7WA6s/tNdsuVw5i7/8h7Hpkp50ANpbErVhsSEC0gviLdnFPjR6sS9fZpVobV3kSNpHl+cv+kYccvLu70o6TihgwBJ2DUMJHSqzlp8wbORZKcHfpKJskfGvBwibJQlHbmaas8uRndWMCtuQBfmfLD5RwLYA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=y3B8N8Ql; 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="y3B8N8Ql" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E8871F00A3A; Wed, 24 Jun 2026 16:33:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782318835; bh=onbBolF/EVoSwKacQsdjPYOYu7Pf8Y6Q3LrsYsIt8f4=; h=From:To:Cc:Subject:Date:Reply-To; b=y3B8N8QlwFCri+f8x5JAW0kOZ//u3EEfwRpioyX+MPIXyzQ4I3I0q4tD93hd0FwoZ 287reSU5QOdlRm+gwuDghjTE2tAwa2DapRkWoQ/o1InInCLli8mfGNd1j3OVVrPx1e BN+ByVP8N7XQBBlE1sQJ61oMhZp/Bi3jregYQ2iw= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-52973: futex: Drop CLONE_THREAD requirement for private default hash alloc Date: Wed, 24 Jun 2026 17:29:57 +0100 Message-ID: <2026062439-CVE-2026-52973-af9c@gregkh> X-Mailer: git-send-email 2.54.0 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=2697; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=cDFgsegOE1tDFQyoZgRYhe+bGu7HmPk3lAncPwDutDk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFk2rF+eNf55LZPY59KhYdLhaCV2VqXPZk/l3G2cvfW6B 920uaU7YlkYBJkYZMUUWb5s4zm6v+KQopeh7WmYOaxMIEMYuDgFYCItagwLJq/8zWMw0faljGTz q/s6r9mTDh+sZVhw6vy/4y86FLdExDnN9OJcGbiSb8ofAA== 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: futex: Drop CLONE_THREAD requirement for private default hash alloc Currently need_futex_hash_allocate_default() depends on strict pthread semantics, abusing CLONE_THREAD. This breaks the non-concurrency assumptions when doing the mm->futex_ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie: BUG: KASAN: slab-use-after-free in futex_hash_put ... where the +1 bias can end up on a percpu counter that mm->futex_ref no longer points at. Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex_ref is already allocated from an earlier CLONE_VM. The Linux kernel CVE team has assigned CVE-2026-52973 to this issue. Affected and fixed versions =========================== Issue introduced in 6.17 with commit d9b05321e21e4b218de4ce8a590bf375f58b6346 and fixed in 6.18.33 with commit 1dcd36420af2da5bd59306dba9caf78e3d248b1d Issue introduced in 6.17 with commit d9b05321e21e4b218de4ce8a590bf375f58b6346 and fixed in 7.0.10 with commit 974ac49a9a068b0591a59f65c63eb06579a13091 Issue introduced in 6.17 with commit d9b05321e21e4b218de4ce8a590bf375f58b6346 and fixed in 7.1 with commit ee9dce44362b2d8132c32964656ab6dff7dfbc6a 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-2026-52973 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: kernel/fork.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/1dcd36420af2da5bd59306dba9caf78e3d248b1d https://git.kernel.org/stable/c/974ac49a9a068b0591a59f65c63eb06579a13091 https://git.kernel.org/stable/c/ee9dce44362b2d8132c32964656ab6dff7dfbc6a