netfilter: ebtables: fix table blob use-after-free
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.2.60 to before 3.3; 3.4.91 to before 3.5; 3.10.41 to before 3.11; 3.12.21 to before 3.13; 3.14.5 to before 3.15 | 3.3, 3.5, 3.11, 3.13, 3.15 | Patch available | CNA |
| Linux | Linux | 3.15 and later | 5.10.173, 5.15.100, 6.1.18, 6.2.5, 6.3 | Patch available | CNA |
- Linux VendorLinux Affected 3.2.60 to before 3.3; 3.4.91 to before 3.5; 3.10.41 to before 3.11; 3.12.21 to before 3.13; 3.14.5 to before 3.15 Fixed in 3.3, 3.5, 3.11, 3.13, 3.15 Patch available CNA
- Linux VendorLinux Affected 3.15 and later Fixed in 5.10.173, 5.15.100, 6.1.18, 6.2.5, 6.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 3.3, 3.5, 3.11, 3.13, 3.15
- Fix · CNA Linux (Linux) Fixed in 5.10.173, 5.15.100, 6.1.18, 6.2.5, 6.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 10
Timeline
- 2026-10-02 Threatist record created from CVE-2023-54243
- 2026-10-03 Alias added: GHSA-2hrc-j4gc-h2p8
- 2026-10-16 CISA SSVC decision points changed
References
Other 5
- https://git.kernel.org/stable/c/9060abce3305ab2354c892c09d5689df51486df5
- https://git.kernel.org/stable/c/dbb3cbbf03b3c52cb390fabec357f1e4638004f5
- https://git.kernel.org/stable/c/3dd6ac973351308d4117eda32298a9f1d68764fd
- https://git.kernel.org/stable/c/cda0e0243bd3c04008fcd37a46b0269fb3c49249
- https://git.kernel.org/stable/c/e58a171d35e32e6e8c37cfe0e8a94406732a331f
More Linux vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2023-54243 · CVE Program
- CVE-2023-54243 · NVD
- FIRST EPSS
- GHSA-2hrc-j4gc-h2p8 · GitHub Advisory Database · CC BY 4.0
- CVE-2023-54243 · Red Hat security data · CC BY 4.0
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