CVE Catalog

CVE-2026-74735

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, in the L2TP modules (pppol2tp and l2tp_dfs), there is a reference leak for tunnels and sessions when closing seq_file files before reaching end-of-file. References stored in private data are not dropped, leading to memory leaks.

Risk Assessment

Repeatedly opening and closing /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels without reading to the end can lead to memory exhaustion and system instability.

Recommendation

Install the latest Linux kernel patch that adds reference dropping in the release functions (pppol2tp_proc_release and l2tp_dfs_seq_release).

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS