# CVE-2026-53070: linux: In the Linux kernel, the following vulnerability has been resolved: sctp: disable BH before calling udp_tunnel_xmit_... CVE-2026-53070 is fixed in 53 products on 1 platform, first by DEBIAN-CVE-2026-53070, released June 25, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-53070 - Priority: High - CVSS: 7.5 (high) - EPSS: 0.0030 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 24, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: sctp: disable BH before calling udp_tunnel_xmit_skb() udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to tunnel xmit functions"), on the path: udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit() dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU. Without local_bh_disable(), the context may move between CPUs, which can break the inc/dec pairing. This may lead to incorrect recursion level detection and cause packets to be dropped in ip(6)_tunnel_xmit() or __dev_queue_xmit(). Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths. In my testing, after enabling the SCTP over UDP: # ip net exec ha sysctl -w net.sctp.udp_port=9899 # ip net exec ha sysctl -w net.sctp.encap_port=9899 # ip net exec hb sysctl -w net.sctp.udp_port=9899 # ip net exec hb sysctl -w net.sctp.encap_port=9899 # ip net exec ha iperf3 -s - without this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender [ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver - with this patch: # ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | bpftool6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23237-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23237-1.md) | Aug 11, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.37.1.160000.2.19 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.73.2.150700.17.41.4 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.37.1.160000.2.19 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-livepatch-6.12.95-124.187 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel-livepatch-6.18.38-73.137 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_18 sles 15.7 | 1-150700.1.5.1 | [SUSE-SU-2026:3130-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3130-1.md) | Jul 20, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_19 sles 15.7 | 1-150700.15.3.4 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.95-1 | [DEBIAN-CVE-2026-53070](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53070.md) | Jun 25, 2026 | | Linux | linux Debian 14 | 7.0.10-1 | [DEBIAN-CVE-2026-53070](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53070.md) | Jun 25, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 | --- Data as of 2026-11-09T19:38:12Z UTC. 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