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 8453A41D118 for ; Fri, 11 Sep 2026 19:53:35 +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=1789156427; cv=none; b=ciJ/ZgOiLGefZNSBvkIm3WMQMPvOnSwyOCmltyZ7bzuxaxunVPLOwlfwdW51d8H41aZEoXg3dLwLmUU9g/7MHSnUo+pUcDcHQ/I6fXr9mGJXimmZfalKP6gK2nKIpoo8tGhxHxkpK0JiflZNGbWx6dW/K4pl6kq6Y+tE4/6qDW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156427; c=relaxed/simple; bh=qyoSrCzR7rGXWeTtV+O6ZgDODaxxXRouUyHmRdOSAlU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IXF5N6F8SNv6LrArhPdJ0D66z6R6gK43Nk+jhXUQNUZKvRnVR/oeGj1UPzTMDmLSpBgdwvDIQsccrGu6Qd0rNvEimkcwLWoRvTHuTlS0kPk7hDBK9lFVDT8epjxPYDTgr6O/2dtxi8Cou2lmIP8bfbZzzVKXcE0yP3t854wflYg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mxgCdtA2; 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="mxgCdtA2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 807221F0089C; Fri, 11 Sep 2026 19:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156414; bh=JyZGZAg/IWx97iLjSLBPpcwJ5IFWfhGdyQswkkYHT2w=; h=From:To:Cc:Subject:Date:Reply-To; b=mxgCdtA2g8b9mjmLS9mFWBzS3lxdetvMwn/kHeMYo99GH9B2K6qGvIl6Sg0WNd9TN LcMMJ/l1Co8mbWpIDtTfyH1rqxvvZ0cWQwAWgast+3sND5AeUXIjx19bHRyuYPn178 B+0BTB+sNsJsEmXril1/7r3Uqsj8k9vETjLCYTAE= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89508: RDMA/ucma: Lock the handler in ucma_set_ib_path() Date: Fri, 11 Sep 2026 21:43:17 +0200 Message-ID: <2026091111-CVE-2026-89508-2d1d@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=3706; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=kV7rpY6CG8qgX2uf5qhtIWyyDUy37OaTYG3defdZ06I=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIsOlBYsCWFokNwTsE3C58/irol/bhjddRWbbF21eu InlQHdgRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEyk/DLDgg73+p8+tcfVJxcc vCf/RCRpuqfRNoYFq37zVx/a/Le/WsFJJGWPue8Rlx/bAA== 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: RDMA/ucma: Lock the handler in ucma_set_ib_path() ucma_set_ib_path() calls ucma_event_handler() straight from the write() path, without the handler lock that keeps ctx->file stable while a uevent is queued. The handler re-reads ctx->file for every dereference: mutex_lock(&ctx->file->mut); /* file A */ list_add_tail(&uevent->list, &ctx->file->event_list); /* file B */ mutex_unlock(&ctx->file->mut); /* file B */ wake_up_interruptible(&ctx->file->poll_wait); /* file B */ A concurrent ucma_migrate_id() reassigns ctx->file while the SET_OPTION caller sleeps in mutex_lock(), so the list_add_tail() lands on file B's event_list while only file A's mutex is held, racing every other user of that list: BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x1aa/0x1c0 Read of size 8 at addr ffff888153c6a418 by task poc_corr/486 Call Trace: __list_add_valid_or_report+0x1aa/0x1c0 ucma_event_handler+0x1be/0xc00 ucma_set_ib_path+0x45e/0x710 ucma_set_option+0x32e/0x590 ucma_write+0x1f9/0x330 Allocated by task 505: ucma_write_cm_event+0x1a1/0x660 Freed by task 505: kfree+0x1da/0x4c0 ucma_get_event+0x5d5/0x7e0 The freed object is a ucma_event that another thread dequeued from file B's list under file B's mutex. File A's mut is left held on top of that, wedging its next writer in uninterruptible sleep. This path needs a bound and address-resolved cm_id, so it requires an RDMA device to be present. Take the handler lock around the call. The Linux kernel CVE team has assigned CVE-2026-89508 to this issue. Affected and fixed versions =========================== Issue introduced in 5.10 with commit 09e328e47a695b0d346598f5d6593ee598e64885 and fixed in 6.12.109 with commit 764586f8f6180084c5a7d622120f526acc6ce0c9 Issue introduced in 5.10 with commit 09e328e47a695b0d346598f5d6593ee598e64885 and fixed in 6.18.50 with commit 28ac2dd416482d1c763c4af5d61af465b387fb50 Issue introduced in 5.10 with commit 09e328e47a695b0d346598f5d6593ee598e64885 and fixed in 7.2.4 with commit 43a7d8ae9f645dc00235cfa4bf57673c20b769f8 Issue introduced in 5.10 with commit 09e328e47a695b0d346598f5d6593ee598e64885 and fixed in 7.3-rc1 with commit ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820 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-2026-89508 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: drivers/infiniband/core/ucma.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/764586f8f6180084c5a7d622120f526acc6ce0c9 https://git.kernel.org/stable/c/28ac2dd416482d1c763c4af5d61af465b387fb50 https://git.kernel.org/stable/c/43a7d8ae9f645dc00235cfa4bf57673c20b769f8 https://git.kernel.org/stable/c/ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820