linux: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: unlink table before deleti...
CVE-2021-47394 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47394, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: unlink table before deleting it syzbot reports following UAF: BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955 nla_strcmp+0xf2/0x130 lib/nlattr.c:836 nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570 nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline] nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064 nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 Problem is that all get operations are lockless, so the commit_mutex held by nft_rcv_nl_event() isn't enough to stop a parallel GET request from doing read-accesses to the table object even after synchronize_rcu(). To avoid this, unlink the table first and store the table objects in on-stack scratch space.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| linux · Debian 12.15 (bookworm) | 5.14.12-1 | DEBIAN-CVE-2021-47394 | May 21, 2024 |
| linux · Debian 13.5 (trixie) | 5.14.12-1 | DEBIAN-CVE-2021-47394 | May 21, 2024 |
| linux · Debian 14 | 5.14.12-1 | DEBIAN-CVE-2021-47394 | May 21, 2024 |
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