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Vulnerability · Published Aug 15, 2026 · Assigned by Linux

CVE-2026-72137xfrm: nat_keepalive: avoid double free on send error

Critical 9.8

In plain English

A critical-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 0.7% (higher than 54% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.7%top 46.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: xfrm: nat_keepalive: avoid double free on send error nat_keepalive_send() frees the keepalive skb whenever the IPv4 or IPv6 send helper reports an error. That cleanup is only correct before the skb is handed to the output path. Once ip_build_and_send_pkt() or ip6_xmit() takes ownership, the networking stack may already have consumed the skb before returning an error, so freeing it again is unsafe. Handle the pre-handoff failure cases inside nat_keepalive_send_ipv4() and nat_keepalive_send_ipv6(), where the caller still owns the skb, and keep nat_keepalive_send() responsible only for family dispatch and the unsupported-family cleanup path.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.101-1DEBIAN-CVE-2026-72137
Debian:14linux7.1.5-1DEBIAN-CVE-2026-72137
Debian:12linux-6.126.12.101-1~deb12u1DEBIAN-CVE-2026-72137
Ubuntu:26.04:LTSlinux7.0.0-34.34UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux7.0.0-34.34USN-8816-1
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-aws7.0.0-1013.13UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-aws7.0.0-1013.13USN-8816-1
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1013.13~24.04.1USN-8816-1
Ubuntu:26.04:LTSlinux-azure7.0.0-1017.17UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1017.17~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1016.16UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1016.16~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-gcp7.0.0-1013.13UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-gcp7.0.0-1013.13USN-8816-2
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1013.13~24.04.1USN-8816-2
Ubuntu:26.04:LTSlinux-gke7.0.0-1007.8USN-8816-4
Ubuntu:26.04:LTSlinux-gke7.0.0-1007.8UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-34.34~24.04.1USN-8816-1
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-34.34~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-ibm7.0.0-1014.14UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-ibm7.0.0-1014.14USN-8816-1
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1024.25~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2022.23UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1014.14USN-8816-2
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1014.14UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-oracle7.0.0-1012.12UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-oracle7.0.0-1012.12USN-8816-1
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1012.12~24.04.1USN-8816-3
Ubuntu:26.04:LTSlinux-raspi7.0.0-1020.20UBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-raspi7.0.0-1020.20USN-8816-1
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-realtime7.0.0-34.34.1USN-8816-1
Ubuntu:26.04:LTSlinux-realtime7.0.0-34.34.1UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-72137
Ubuntu:26.04:LTSlinux-riscv7.0.0-34.34.1UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-72137
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-34.34.1~24.04.1UBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-72137
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-72137

Affected products (as reported)

VendorProductVersions
Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – before d0a4dc7efa825bce60a8da8f7d43c864a159abdef531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – before 5b0c4c916f202b8fd13d12afb6af62b385622f81f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – before a8a7e6a9ff8a4c1f067694ddbd44be67fdf36693f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – before 226f4a490d1a938fc838d8f8c46a4eca864c0d78
Linux Linux 6.11

References