cbcvebase.
CVE-2026-23286
published 2026-03-25

CVE-2026-23286: In the Linux kernel, the following vulnerability has been resolved: atm: lec: fix null-ptr-deref in lec_arp_clear_vccs syzkaller reported a null-ptr-deref in…

PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.13%
2.6th percentile
In the Linux kernel, the following vulnerability has been resolved: atm: lec: fix null-ptr-deref in lec_arp_clear_vccs syzkaller reported a null-ptr-deref in lec_arp_clear_vccs(). This issue can be easily reproduced using the syzkaller reproducer. In the ATM LANE (LAN Emulation) module, the same atm_vcc can be shared by multiple lec_arp_table entries (e.g., via entry->vcc or entry->recv_vcc). When the underlying VCC is closed, lec_vcc_close() iterates over all ARP entries and calls lec_arp_clear_vccs() for each matched entry. For example, when lec_vcc_close() iterates through the hlists in priv->lec_arp_empty_ones or other ARP tables: 1. In the first iteration, for the first matched ARP entry sharing the VCC, lec_arp_clear_vccs() frees the associated vpriv (which is vcc->user_back) and sets vcc->user_back to NULL. 2. In the second iteration, for the next matched ARP entry sharing the same VCC, lec_arp_clear_vccs() is called again. It obtains a NULL vpriv from vcc->user_back (via LEC_VCC_PRIV(vcc)) and then attempts to dereference it via `vcc->pop = vpriv->old_pop`, leading to a null-ptr-deref crash. Fix this by adding a null check for vpriv before dereferencing it. If vpriv is already NULL, it means the VCC has been cleared by a previous call, so we can safely skip the cleanup and just clear the entry's vcc/recv_vcc pointers. The entire cleanup block (including vcc_release_async()) is placed inside the vpriv guard because a NULL vpriv indicates the VCC has already been fully released by a prior iteration — repeating the teardown would redundantly set flags and trigger callbacks on an already-closing socket. The Fixes tag points to the initial commit because the entry->vcc path has been vulnerable since the original code. The entry->recv_vcc path was later added by commit 8d9f73c0ad2f ("atm: fix a memory leak of vcc->user_back") with the same pattern, and both paths are fixed here.

Affected

63 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.19.8-1 (forky)linux 6.19.8-1 (forky)
linuxlinux
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8aff65a82b6389ec674d46e5b3d3ae6f07db5e3e8aff65a82b6389ec674d46e5b3d3ae6f07db5e3e
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 30c9744a989feb22cfbb84170eb0e038a7a2c1da30c9744a989feb22cfbb84170eb0e038a7a2c1da
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e9665986eb127290ceb535bd5d04d7a84265d94fe9665986eb127290ceb535bd5d04d7a84265d94f
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 622062f24644b4536d3f437e0cf7a8c4bb421665622062f24644b4536d3f437e0cf7a8c4bb421665
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2d9f57ea29a1f1772373b98a509b44d49fda609e2d9f57ea29a1f1772373b98a509b44d49fda609e
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7ea92ab075d809ec8a96669a5ecf00f7520578757ea92ab075d809ec8a96669a5ecf00f752057875
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5f1cfea7921f5c126a441d973690eeba52677b645f1cfea7921f5c126a441d973690eeba52677b64
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 101bacb303e89dc2e0640ae6a5e0fb97c4eb45bb101bacb303e89dc2e0640ae6a5e0fb97c4eb45bb
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.19.8-16.19.8-1
linuxlinux_kernel>= 2.6.12 < 6.1.1676.1.167
linuxlinux_kernel>= 2.6.12.1 < 5.10.2535.10.253
linuxlinux_kernel>= 5.11 < 5.15.2035.15.203
linuxlinux_kernel>= 5.16 < 6.1.1676.1.167
linuxlinux_kernel>= 6.13 < 6.18.176.18.17
linuxlinux_kernel>= 6.13.0 < 6.18.176.18.17
linuxlinux_kernel>= 6.19 < 6.19.76.19.7
linuxlinux_kernel>= 6.19.0 < 6.19.76.19.7
linuxlinux_kernel>= 6.2 < 6.6.1306.6.130
linuxlinux_kernel>= 6.2.0 < 6.6.1306.6.130
linuxlinux_kernel>= 6.7 < 6.12.776.12.77
linuxlinux_kernel>= 6.7.0 < 6.12.776.12.77

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_ubuntu7.1HIGH
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
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