# CVE-2026-23286: atm: lec: fix null-ptr-deref in lec_arp_clear_vccs CVE-2026-23286 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2026-23286, released March 25, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-23286 - Priority: Routine - CVSS: 5.5 (Moderate) - EPSS: 0.0013 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 25, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23286 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-uek ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-doc ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-doc ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-tools ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek-tools ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-204.92.4.2.el9uek | [ELSA-2026-50372](https://patchblox.com/security/data/fix/linux/elsa-2026-50372.md) | Jul 2, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.170-1 | [DEBIAN-CVE-2026-23286](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23286.md) | Mar 25, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.85-1 | [DEBIAN-CVE-2026-23286](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23286.md) | Mar 25, 2026 | | Linux | linux Debian 14 | 6.19.8-1 | [DEBIAN-CVE-2026-23286](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23286.md) | Mar 25, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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