CVE-2026-74735
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.
How to fix
- Linux Linuxc38b723858a51d6ca4e56470b9f1087f23276772, bd897e414451fb34dfdf08b31899180e5ab7149b, bdf83613781956cc39798ed08321f74ab0467f4d, 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500, ebe2774e956482dd3c70b8991f6f7654356339e6, 9006c116dd111d457bf5d074990210f70a4ad2c8, 3.17, 4.17 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < c38b723858a51d6ca4e56470b9f1087f23276772, 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < bd897e414451fb34dfdf08b31899180e5ab7149b, 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < bdf83613781956cc39798ed08321f74ab0467f4d, 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500, 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < ebe2774e956482dd3c70b8991f6f7654356339e6, 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ≤ v < 9006c116dd111d457bf5d074990210f70a4ad2c8, f6104e9ae04462523c372928b1173766a771ef95, 7f8e401f9e612df2a95c1ef76217c00181389bb5, c712ed63e9b33d9a282fbd92ce25c64918c3129f, 9a8863e8a8def9d88583cd9c60db38a008e6b8cf, 3.16.60 ≤ v < 3.17, 4.16.6 ≤ v < 4.17, 4.17 | c38b723858a51d6ca4e56470b9f1087f23276772, bd897e414451fb34dfdf08b31899180e5ab7149b, bdf83613781956cc39798ed08321f74ab0467f4d, 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500, ebe2774e956482dd3c70b8991f6f7654356339e6, 9006c116dd111d457bf5d074990210f70a4ad2c8, 3.17, 4.17 |
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