{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53070","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-06-09T07:44:35.382Z","datePublished":"2026-06-24T16:30:11.816Z","dateUpdated":"2026-07-04T11:50:49.194Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-07-04T11:50:49.194Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: disable BH before calling udp_tunnel_xmit_skb()\n\nudp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with\nBH disabled.  After commit 6f1a9140ecda (\"add xmit recursion limit to\ntunnel xmit functions\"), on the path:\n\n  udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit()\n\ndev_xmit_recursion_inc()/dec() must stay balanced on the same CPU.\n\nWithout local_bh_disable(), the context may move between CPUs, which can\nbreak the inc/dec pairing. This may lead to incorrect recursion level\ndetection and cause packets to be dropped in ip(6)_tunnel_xmit() or\n__dev_queue_xmit().\n\nFix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths.\n\nIn my testing, after enabling the SCTP over UDP:\n\n  # ip net exec ha sysctl -w net.sctp.udp_port=9899\n  # ip net exec ha sysctl -w net.sctp.encap_port=9899\n  # ip net exec hb sysctl -w net.sctp.udp_port=9899\n  # ip net exec hb sysctl -w net.sctp.encap_port=9899\n\n  # ip net exec ha iperf3 -s\n\n- without this patch:\n\n  # ip net exec hb iperf3 -c 192.168.0.1 --sctp\n  [  5]   0.00-10.00  sec  37.2 MBytes  31.2 Mbits/sec  sender\n  [  5]   0.00-10.00  sec  37.1 MBytes  31.1 Mbits/sec  receiver\n\n- with this patch:\n\n  # ip net exec hb iperf3 -c 192.168.0.1 --sctp\n  [  5]   0.00-10.00  sec  3.14 GBytes  2.69 Gbits/sec  sender\n  [  5]   0.00-10.00  sec  3.14 GBytes  2.69 Gbits/sec  receiver"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"}}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/ipv6.c","net/sctp/protocol.c"],"versions":[{"version":"046c052b475e7119b6a30e3483e2888fc606a2f8","lessThan":"be3bfcb34bda04f6a350710db471d4133f950f2c","status":"affected","versionType":"git"},{"version":"046c052b475e7119b6a30e3483e2888fc606a2f8","lessThan":"0de7db2eb27e82b983157016fa604b1ba664ae5f","status":"affected","versionType":"git"},{"version":"046c052b475e7119b6a30e3483e2888fc606a2f8","lessThan":"790093245e35040c2adb15f48970020425aa3f47","status":"affected","versionType":"git"},{"version":"046c052b475e7119b6a30e3483e2888fc606a2f8","lessThan":"2cd7e6971fc2787408ceef17906ea152791448cf","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/ipv6.c","net/sctp/protocol.c"],"versions":[{"version":"5.11","status":"affected"},{"version":"0","lessThan":"5.11","status":"unaffected","versionType":"semver"},{"version":"6.12.95","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.37","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.10","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.12.95"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.18.37"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/be3bfcb34bda04f6a350710db471d4133f950f2c"},{"url":"https://git.kernel.org/stable/c/0de7db2eb27e82b983157016fa604b1ba664ae5f"},{"url":"https://git.kernel.org/stable/c/790093245e35040c2adb15f48970020425aa3f47"},{"url":"https://git.kernel.org/stable/c/2cd7e6971fc2787408ceef17906ea152791448cf"}],"title":"sctp: disable BH before calling udp_tunnel_xmit_skb()","x_generator":{"engine":"bippy-1.2.0"}}}}