# CVE-2023-54243: linux: In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: fix table blob use-after-fr... CVE-2023-54243 is fixed in 20 products on 1 platform, first by ALAS2023-2023-138, released March 20, 2023. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2023-54243 - Priority: High - CVSS: 7.8 (high) - EPSS: 0.0015 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 20, 2023 ## Description In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: fix table blob use-after-free We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not. t = find_table_lock(net, repl->name, &ret, &ebt_mutex); ... this can return a valid table, with ret != 0. This bug causes update of table->private with the new blob, but then frees the blob right away in the caller. Syzbot report: BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74 Workqueue: netns cleanup_net Call Trace: kasan_report+0xbf/0x1f0 mm/kasan/report.c:517 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 ... ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | bpftool-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-headers amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-libbpf-static amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-livepatch-6.1.19-30.43 amzn 2023 | 1.0-0.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | kernel-tools-devel amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | linux Debian 12.15 (bookworm) | 6.1.20-1 | [DEBIAN-CVE-2023-54243](https://patchblox.com/security/data/fix/linux/debian-cve-2023-54243.md) | Dec 30, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.1.20-1 | [DEBIAN-CVE-2023-54243](https://patchblox.com/security/data/fix/linux/debian-cve-2023-54243.md) | Dec 30, 2025 | | Linux | linux Debian 14 | 6.1.20-1 | [DEBIAN-CVE-2023-54243](https://patchblox.com/security/data/fix/linux/debian-cve-2023-54243.md) | Dec 30, 2025 | | Linux | perf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | perf-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | python3-perf amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | | Linux | python3-perf-debuginfo amzn 2023 | 6.1.19-30.43.amzn2023 | [ALAS2023-2023-138](https://patchblox.com/security/data/fix/linux/alas2023-2023-138.md) | Mar 20, 2023 | --- Data as of 2026-11-08T06:59:42Z UTC. 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