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Vulnerability · Published Jul 19, 2026 · Assigned by Linux

CVE-2026-63828apparmor: mediate the implicit connect of TCP fast open sendmsg

High 8.4

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.4High
Exploit odds (30 days)0.2%top 93.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling1Public PoC

Official description

In the Linux kernel, the following vulnerability has been resolved: apparmor: mediate the implicit connect of TCP fast open sendmsg sendmsg()/sendto() with MSG_FASTOPEN is a combination of connect(2) and write(2): it opens the connection in the SYN. apparmor_socket_sendmsg() only checks AA_MAY_SEND, so a profile that grants send but denies connect lets a confined task open an outbound TCP/MPTCP connection that connect(2) would have refused, bypassing connect mediation. Mediate the implicit connect when MSG_FASTOPEN is set and a destination is supplied. Add it to apparmor_socket_sendmsg() (not the shared aa_sock_msg_perm() helper, which recvmsg also uses) and call aa_sk_perm() directly, mirroring the selinux and tomoyo fixes. sk_is_tcp() does not cover MPTCP fast open, so the SOCK_STREAM/IPPROTO_MPTCP arm is explicit.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.177-1DEBIAN-CVE-2026-63828
Debian:13linux6.12.95-1DEBIAN-CVE-2026-63828
Debian:14linux7.1.3-1DEBIAN-CVE-2026-63828
Ubuntu:22.04:LTSlinux5.15.0-198.208UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux6.8.0-147.147UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-aws6.8.0-1067.70UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure6.8.0-1071.79UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1069.76UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gcp6.8.0-1071.79UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gke6.8.0-1066.74UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1052.56UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-ibm6.8.0-1067.68UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-147.147.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1035.38UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oracle6.8.0-1064.67UBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-63828
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-63828
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-63828
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84UBUNTU-CVE-2026-63828

Affected products (as reported)

VendorProductVersions
Linux Linux cf60af03ca4e71134206809ea892e49b92a88896 – before a16714e7cf2baa98ba2efddd5d6cbac641f4e76bcf60af03ca4e71134206809ea892e49b92a88896 – before 20383429b56974507c465d016e5238b189f7a246cf60af03ca4e71134206809ea892e49b92a88896 – before 7f57428ce00891d26b0f087ef754a4d820ec83aacf60af03ca4e71134206809ea892e49b92a88896 – before faea60deaa05c76f0772650f42eafde12bd39d93cf60af03ca4e71134206809ea892e49b92a88896 – before 07b71c342382b854ab8030b244aeab6a7228ad7dcf60af03ca4e71134206809ea892e49b92a88896 – before 4a69b83045d3195d5b9a9b053ad840ddb2998b4ecf60af03ca4e71134206809ea892e49b92a88896 – before 45ebb934ea50b436ce49b2f159f090dab0d7fa28cf60af03ca4e71134206809ea892e49b92a88896 – before 4d587cd8a72155089a627130bbd4716ec0856e21
Linux Linux 3.6

References