Log in Start free

Vulnerability · Published Aug 26, 2026 · Assigned by Linux

CVE-2026-74735l2tp: fix tunnel and session refcount leak on seq_file release

Unrated

In plain English

A 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 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS )–Not rated
Exploit odds (30 days)0.2%top 88.0% 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: l2tp: fix tunnel and session refcount leak on seq_file release In pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state (pd->tunnel and pd->session) is kept in seq_file private data to allow iteration across multiple read() system calls. However, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels before reading to end-of-file (EOF), any tunnel or session reference stored in pd->tunnel / pd->session is left un-dropped when seq_file private data is freed. Fix this by dropping any remaining pd->tunnel and pd->session references in pppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2026-74735
Debian:13linux6.12.111-1DEBIAN-CVE-2026-74735
Debian:14linux7.1.10-1DEBIAN-CVE-2026-74735
Debian:12linux-6.126.12.111-1~deb12u1DEBIAN-CVE-2026-74735
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux7.0.0-42.42UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-aws7.0.0-1016.17UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-aws-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-fde-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-gcp7.0.0-1016.18UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gcp-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-42.42~24.04.1UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-ibm7.0.0-1017.17UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidia-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-nvidia-bosno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1017.17UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-oracle7.0.0-1015.16UBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-oracle-7.0no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-74735
Ubuntu:26.04:LTSlinux-riscv7.0.0-42.42.1UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-42.42.1~24.04.1UBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-vmwareno fix listedUBUNTU-CVE-2026-74735
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-74735
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2026-74735

Affected products (as reported)

VendorProductVersions
Linux Linux 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before c38b723858a51d6ca4e56470b9f1087f232767720e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before bd897e414451fb34dfdf08b31899180e5ab7149b0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before bdf83613781956cc39798ed08321f74ab0467f4d0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd5000e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before ebe2774e956482dd3c70b8991f6f7654356339e60e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 – before 9006c116dd111d457bf5d074990210f70a4ad2c8f6104e9ae04462523c372928b1173766a771ef957f8e401f9e612df2a95c1ef76217c00181389bb5
Linux Linux 4.17

References