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 EEF8C39901C for ; Wed, 3 Jun 2026 16:19:26 +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=1780503568; cv=none; b=Ty8hn2ZeHjIx0nb+Pte7ljGem9hhrXdPJCxXwS+CoZS/BjKl8RfEgCPWxSQi+XR3FfqLCSHHmcVQa4D9X6womv6xxnPhUX5Xw5QETedsI6KTOHab6pAkmM9Ei8c44TDklUddRxVzIPLAJOP+/UVGooEjC7zBxGFq63BGXPKD/Lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780503568; c=relaxed/simple; bh=DG6S7Uae8SciG9QODG3et7Ak2bQFe067ZvOneunslrg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=sRxRisA4DmACS0v4ONvNScx2TyQXcvX2XYirGGCO+MoBvR/V7XvYTvB/0uTL6Ysh4FQPPXV5nIlGnQAU3pqxB8aR0/f1kGSXr76K2scOiszHPJBDHwWsmuDlMjeiXCRKGXSzPyTsGHj0GaBNY8sRISd1CCxP5lrGhM9qrWFM2Uk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MD2V68S2; 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="MD2V68S2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB8961F00893; Wed, 3 Jun 2026 16:19:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780503566; bh=ZuOfTTEyu1zegYNdx3+b9Kgyts3rfuA5Mh9taZ/NBVY=; h=From:To:Cc:Subject:Date:Reply-To; b=MD2V68S2pck/34Jis258mhhfYcUsaR+CAJbMwhhBwVe8gmLZMSZzrbpWNponlEaYj vvCDlit2OZwWZY+3R1YzJsSoo3vu+F5BuJ+q/C4nwpg3dYpswkKsJ+heyZjkMHOJwc f4DEU6jOH5Q5YLe3FblU02cSASEciM9PduhXwEFs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-46273: ibmveth: Disable GSO for packets with small MSS Date: Wed, 3 Jun 2026 18:18:28 +0200 Message-ID: <2026060327-CVE-2026-46273-e8d0@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=4497; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=68vTpCGc+XYe9dPU43SwVyy80CvpSWZwaT3MX5qBob8=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkKwZfj5rQ8u2n30sdkx8LFvPOlV716sH5aqEHnsZL2j rINCmIqHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjAR22qG+ZFLDB9dL77LbJmY qnzBSZHx2t4v/xgWrDhu+6j1yYZcdoeXKdve7JkSMf9LMwA= 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: ibmveth: Disable GSO for packets with small MSS Some physical adapters on Power systems do not support segmentation offload when the MSS is less than 224 bytes. Attempting to send such packets causes the adapter to freeze, stopping all traffic until manually reset. Implement ndo_features_check to disable GSO for packets with small MSS values. The network stack will perform software segmentation instead. The 224-byte minimum matches ibmvnic commit ("ibmvnic: Enforce stronger sanity checks on GSO packets") which uses the same physical adapters in SEA configurations. The issue occurs specifically when the hardware attempts to perform segmentation (gso_segs > 1) with a small MSS. Single-segment GSO packets (gso_segs == 1) do not trigger the problematic LSO code path and are transmitted normally without segmentation. Add an ndo_features_check callback to disable GSO when MSS < 224 bytes. Also call vlan_features_check() to ensure proper handling of VLAN packets, particularly QinQ (802.1ad) configurations where the hardware parser may not support certain offload features. Validated using iptables to force small MSS values. Without the fix, the adapter freezes. With the fix, packets are segmented in software and transmission succeeds. Comprehensive regression testing completedd (MSS tests, performance, stability). The Linux kernel CVE team has assigned CVE-2026-46273 to this issue. Affected and fixed versions =========================== Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 5.10.258 with commit 86fc64584811d43c9ccd74447de58620189d8b77 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 5.15.209 with commit 9a5e984d7af910e46dcbed3ce77873e000a4f77d Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 6.1.175 with commit 1cdf5dbcec988d06f5f720bdf89e91073f77fa10 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 6.6.140 with commit 82bc89fbb82d9396fb4eaee8720ea85e2e787957 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 6.12.88 with commit db8012c631cb845e9ae2b4b531e17d86c9519755 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 6.18.30 with commit c1f261863e65b508f37416dfbc5c5d911c9b9233 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 7.0.7 with commit 3af24f0c4c31f18a4a2d927990759194832bb6e9 Issue introduced in 4.2 with commit 8641dd85799f85bef5f0d1f87356aaa12cb2195e and fixed in 7.1-rc2 with commit cc427d24ac6442ffdeafd157a63c7c5b73ed4de4 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-2026-46273 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/net/ethernet/ibm/ibmveth.c drivers/net/ethernet/ibm/ibmveth.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/86fc64584811d43c9ccd74447de58620189d8b77 https://git.kernel.org/stable/c/9a5e984d7af910e46dcbed3ce77873e000a4f77d https://git.kernel.org/stable/c/1cdf5dbcec988d06f5f720bdf89e91073f77fa10 https://git.kernel.org/stable/c/82bc89fbb82d9396fb4eaee8720ea85e2e787957 https://git.kernel.org/stable/c/db8012c631cb845e9ae2b4b531e17d86c9519755 https://git.kernel.org/stable/c/c1f261863e65b508f37416dfbc5c5d911c9b9233 https://git.kernel.org/stable/c/3af24f0c4c31f18a4a2d927990759194832bb6e9 https://git.kernel.org/stable/c/cc427d24ac6442ffdeafd157a63c7c5b73ed4de4