CVE-2023-54243

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.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/3dd6ac973351308d4117eda32298a9f1d68764fd
https://git.kernel.org/stable/c/9060abce3305ab2354c892c09d5689df51486df5
https://git.kernel.org/stable/c/cda0e0243bd3c04008fcd37a46b0269fb3c49249
https://git.kernel.org/stable/c/dbb3cbbf03b3c52cb390fabec357f1e4638004f5
https://git.kernel.org/stable/c/e58a171d35e32e6e8c37cfe0e8a94406732a331f

Configurations

No configuration.

History

No history.

Information

Published : 2025-12-30 13:16

Updated : 2026-08-04 11:16

NVD link : CVE-2023-54243

Mitre link : CVE-2023-54243

CVE.ORG link : CVE-2023-54243

JSON object : View

Products Affected

No product.

CWE

No CWE.

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"semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.100", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.18", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.2.5", "versionType": "semver", "lessThanOrEqual": "6.2.*"}, {"status": "unaffected", "version": "6.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/bridge/netfilter/ebtables.c", "net/ipv4/netfilter/ip_tables.c", "net/ipv6/netfilter/ip6_tables.c"], "defaultStatus": "affected"}]}], "published": "2025-12-30T13:16:12.880", "references": [{"url": "https://git.kernel.org/stable/c/3dd6ac973351308d4117eda32298a9f1d68764fd", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9060abce3305ab2354c892c09d5689df51486df5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/cda0e0243bd3c04008fcd37a46b0269fb3c49249", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dbb3cbbf03b3c52cb390fabec357f1e4638004f5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e58a171d35e32e6e8c37cfe0e8a94406732a331f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Deferred", "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebtables: fix table blob use-after-free\n\nWe are not allowed to return an error at this point.\nLooking at the code it looks like ret is always 0 at this\npoint, but its not.\n\nt = find_table_lock(net, repl->name, &ret, &ebt_mutex);\n\n... this can return a valid table, with ret != 0.\n\nThis bug causes update of table->private with the new\nblob, but then frees the blob right away in the caller.\n\nSyzbot report:\n\nBUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\nRead of size 4 at addr ffffc90005425000 by task kworker/u4:4/74\nWorkqueue: netns cleanup_net\nCall Trace:\n kasan_report+0xbf/0x1f0 mm/kasan/report.c:517\n __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\n ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372\n ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169\n cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613\n...\n\nip(6)tables appears to be ok (ret should be 0 at this point) but make\nthis more obvious."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: ebtables: corregir uso despu\u00e9s de liberaci\u00f3n de blob de tabla\n\nNo se nos permite devolver un error en este punto.\nAl mirar el c\u00f3digo parece que ret siempre es 0 en este\npunto, pero no lo es.\n\nt = find_table_lock(net, repl->name, &ret, &ebt_mutex);\n\n... esto puede devolver una tabla v\u00e1lida, con ret != 0.\n\nEste error causa la actualizaci\u00f3n de table->private con el nuevo\nblob, pero luego libera el blob inmediatamente en el llamador.\n\nInforme de Syzbot:\n\nERROR: KASAN: vmalloc-fuera-de-l\u00edmites en __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\nLectura de tama\u00f1o 4 en la direcci\u00f3n ffffc90005425000 por la tarea kworker/u4:4/74\nCola de trabajo: netns cleanup_net\nTraza de llamada:\n kasan_report+0xbf/0x1f0 mm/kasan/report.c:517\n __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\n ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372\n ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169\n cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613\n...\n\nip(6)tables parece estar bien (ret deber\u00eda ser 0 en este punto) pero hacer\nesto m\u00e1s obvio."}], "lastModified": "2026-08-04T11:16:38.120", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}