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 0D3E8312837 for ; Wed, 24 Jun 2026 16:35:06 +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=1782318907; cv=none; b=J7+w2EJS0m55gcnJB5GjU0t+aY0xiY48PkiUb30CjIkMTIpHD4+siGzySPhOfCuPtlAd/e32EB44ILf/pBhiMm7nmovECW6s9N/5HBPoMNWsX5ThLn93QkI7NI2eu2k6wjRWwOXBeQC6xS9EZT1rcUTzGCGW0N1auL/gU+5SgJI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782318907; c=relaxed/simple; bh=eE4lkkiKmXMGX57Qw2/L7Jb/DXB2tvc/Wspnah1yiWY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RsWaS4zSQe1k3Z5MDVWwIkqbl3aCF6Ap1g1ufm6VUWaUsPR/ZCCpZb4HjrENjAGfobL7Wz9X+aFklG/gZtClFEnvgVSofWuibK9rTF8r/xf8BIzTO7Ex76j7DoX76ik6AO/RnscAtOE3e9NLcRR55xuNRdzqUTg5c/Niy5CHjBg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UtdsIW0h; 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="UtdsIW0h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 323D21F000E9; Wed, 24 Jun 2026 16:35:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782318906; bh=0blG3Dib0aScoaXV2LesNprr4p5VzHZI1ZSiofzev/4=; h=From:To:Cc:Subject:Date:Reply-To; b=UtdsIW0hA5gy4GFZD7JSHZv95Y8u1oXO+8d0ZKOnBsyepLPpKqveXw0o7CqPF+R7f kJ0Nfkg59PVOst8ruxZptq3YEhxJ3dY6AQnV0Rv2NHzmiDqMNcHyMRRmugiJkFzm7w bLJ6wmfw97JQdg6dX59r57ODiNUw6raoojy8Bu9E= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-53012: nexthop: fix IPv6 route referencing IPv4 nexthop Date: Wed, 24 Jun 2026 17:30:36 +0100 Message-ID: <2026062450-CVE-2026-53012-8705@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=4310; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=OyRWQIBZYmrOHyBPtlLLjmRtnWxo38Ndl7AxqsH51ss=; b=owGbwMvMwCRo6H6F97bub03G02pJDFk2rP9WZZTMyuHwN085GFTwvDPub47G0pRPt4xPB3w89 q3aWX12RywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEwkupRhwckNcZcPmZ7MjtKz fX2+p9f+VVwUF8P8gngHp8n/uszjy6tu8HWlnpS/L60KAA== 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: nexthop: fix IPv6 route referencing IPv4 nexthop syzbot reported a panic [1] [2]. When an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag of all groups containing this nexthop is not updated. This is because nh_group_v4_update is only called when replacing AF_INET to AF_INET6, but the reverse direction (AF_INET6 to AF_INET) is missed. This allows a stale has_v4=false to bypass fib6_check_nexthop, causing IPv6 routes to be attached to groups that effectively contain only AF_INET members. Subsequent route lookups then call nexthop_fib6_nh() which returns NULL for the AF_INET member, leading to a NULL pointer dereference. Fix by calling nh_group_v4_update whenever the family changes, not just AF_INET to AF_INET6. Reproducer: # AF_INET6 blackhole ip -6 nexthop add id 1 blackhole # group with has_v4=false ip nexthop add id 100 group 1 # replace with AF_INET (no -6), has_v4 stays false ip nexthop replace id 1 blackhole # pass stale has_v4 check ip -6 route add 2001:db8::/64 nhid 100 # panic ping -6 2001:db8::1 [1] https://syzkaller.appspot.com/bug?id=e17283eb2f8dcf3dd9b47fe6f67a95f71faadad0 [2] https://syzkaller.appspot.com/bug?id=8699b6ae54c9f35837d925686208402949e12ef3 The Linux kernel CVE team has assigned CVE-2026-53012 to this issue. Affected and fixed versions =========================== Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 5.10.258 with commit ceffe81a0be92afc0cd1340bc8ca46559cce9bb4 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 5.15.209 with commit 9c2d6770a5f4545a307eb66979bef7656a34d621 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 6.1.175 with commit 6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 6.6.141 with commit aaac3bed034239e1d75732211d9b05f30b0b4f35 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 6.12.91 with commit ad85961004fd4bd2f31209ac4b07612c6cefb9e7 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 6.18.33 with commit 613c8f4a501421dd258b07ea614205d4e16ec845 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 7.0.10 with commit b3b7e850e1541f0520c4a12ec884255c30427ff6 Issue introduced in 5.3 with commit 7bf4796dd09984ad1612877a82d0d139c70ae27f and fixed in 7.1 with commit 29c95185ba32b621fbc3800fb86e7dc3edf5c2be 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-2026-53012 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/ipv4/nexthop.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/ceffe81a0be92afc0cd1340bc8ca46559cce9bb4 https://git.kernel.org/stable/c/9c2d6770a5f4545a307eb66979bef7656a34d621 https://git.kernel.org/stable/c/6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8 https://git.kernel.org/stable/c/aaac3bed034239e1d75732211d9b05f30b0b4f35 https://git.kernel.org/stable/c/ad85961004fd4bd2f31209ac4b07612c6cefb9e7 https://git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845 https://git.kernel.org/stable/c/b3b7e850e1541f0520c4a12ec884255c30427ff6 https://git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be