AI Score
Confidence
Low
EPSS
Percentile
9.0%
SSVC
Exploitation
none
Automatable
no
Technical Impact
partial
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.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6001a930ce03",
"lessThan": "f65c73d3aabb",
"versionType": "git"
},
{
"status": "affected",
"version": "6001a930ce03",
"lessThan": "a499b03bf36b",
"versionType": "git"
}
],
"programFiles": [
"net/netfilter/nf_tables_api.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.12",
"versionType": "custom"
},
{
"status": "unaffected",
"version": "5.14.10",
"versionType": "custom",
"lessThanOrEqual": "5.14.*"
},
{
"status": "unaffected",
"version": "5.15",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/netfilter/nf_tables_api.c"
],
"defaultStatus": "affected"
}
]