netfilter: br_netfilter: do not check confirmed bit in br_nf_local_in() after confirm
In the Linux kernel, the following vulnerability has been resolved: netfilter: br_netfilter: do not check confirmed bit in br_nf_local_in() after confirm When send a broadcast packet to a tap device, which was added to a bridge, br_nf_local_in() is called to confirm the conntrack. If another conntrack with the same hash value is added to the hash table, which can be triggered by a normal packet to a non-bridge device, the below warning may happen. ------------[ cut here ]------------ WARNING: CPU: 1 PID: 96 at net/bridge/br_netfilter_hooks.c:632 br_nf_local_in+0x168/0x200 CPU: 1 UID: 0 PID: 96 Comm: tap_send Not tainted 6.17.0-rc2-dirty #44 PREEMPT(voluntary) RIP: 0010:br_nf_local_in+0x168/0x200 Call Trace: nf_hook_slow+0x3e/0xf0 br_pass_frame_up+0x103/0x180 br_handle_frame_finish+0x2de/0x5b0 br_nf_hook_thresh+0xc0/0x120 br_nf_pre_routing_finish+0x168/0x3a0 br_nf_pre_routing+0x237/0x5e0 br_handle_frame+0x1ec/0x3c0 __netif_receive_skb_core+0x225/0x1210 __netif_receive_skb_one_core+0x37/0xa0 netif_receive_skb+0x36/0x160 tun_get_user+0xa54/0x10c0 tun_chr_write_iter+0x65/0xb0 vfs_write+0x305/0x410 ksys_write+0x60/0xd0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f ---[ end trace 0000000000000000 ]--- To solve the hash conflict, nf_ct_resolve_clash() try to merge the conntracks, and update skb->_nfct. However, br_nf_local_in() still use the old ct from local variable 'nfct' after confirm(), which leads to this warning. If confirm() does not insert the conntrack
CVE-2025-39894
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-39894
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7c3f28599652acf431a2211168de4a583f30b6d5",
"lessThan": "d00c8b0daf56012f69075e3377da67878c775e4c",
"versionType": "git"
},
{
"status": "affected",
"version": "2b1414d5e94e477edff1d2c79030f1d742625ea0",
"lessThan": "ccbad4803225eafe0175d3cb19f0d8d73b504a94",
"versionType": "git"
},
{
"status": "affected",
"version": "80cd0487f630b5382734997c3e5e3003a77db315",
"lessThan": "50db11e2bbb635e38e3dd096215580d6adb41fb0",
"versionType": "git"
},
{
"status": "affected",
"version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9",
"lessThan": "c47ca77fee9071aa543bae592dd2a384f895c8b6",
"versionType": "git"
},
{
"status": "affected",
"version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9",
"lessThan": "a74abcf0f09f59daeecf7a3ba9c1d690808b0afe",
"versionType": "git"
},
{
"status": "affected",
"version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9",
"lessThan": "479a54ab92087318514c82428a87af2d7af1a576",
"versionType": "git"
},
{
"status": "affected",
"version": "cb734975b0ffa688ff6cc0eed463865bf07b6c01",
"versionType": "git"
},
{
"status": "affected",
"version": "5.15.151",
"lessThan": "5.15.192",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.81",
"lessThan": "6.1.151",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.21",
"lessThan": "6.6.105",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.7.9",
"lessThan": "6.8",
"versionType": "semver"
}
],
"programFiles": [
"net/bridge/br_netfilter_hooks.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.192",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.151",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.105",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.46",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.16.6",
"versionType": "semver",
"lessThanOrEqual": "6.16.*"
},
{
"status": "unaffected",
"version": "6.17",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/bridge/br_netfilter_hooks.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-39894
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #30636 · Revision 1
- Added to Heist Feed
- Publisher date