netfilter: nf_conntrack: fix crash due to removal of uninitialised entry
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: fix crash due to removal of uninitialised entry A crash in conntrack was reported while trying to unlink the conntrack entry from the hash bucket list: [exception RIP: __nf_ct_delete_from_lists+172] [..] #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack] #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack] #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack] [..] The nf_conn struct is marked as allocated from slab but appears to be in a partially initialised state: ct hlist pointer is garbage; looks like the ct hash value (hence crash). ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected ct->timeout is 30000 (=30s), which is unexpected. Everything else looks like normal udp conntrack entry. If we ignore ct->status and pretend its 0, the entry matches those that are newly allocated but not yet inserted into the hash: - ct hlist pointers are overloaded and store/cache the raw tuple hash - ct->timeout matches the relative time expected for a new udp flow rather than the absolute 'jiffies' value. If it were not for the presence of IPS_CONFIRMED, __nf_conntrack_find_get() would have skipped the entry. Theory is that we did hit following race: cpu x cpu y cpu z found entry E found entry E E is expired nf_ct_delete() return E to rcu slab init_conntrack E is re-inited, ct->status set to 0 reply tuplehash hnnode.
CVE-2025-38472
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-2025-38472
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": "1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912",
"lessThan": "a47ef874189d47f934d0809ae738886307c0ea22",
"versionType": "git"
},
{
"status": "affected",
"version": "1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912",
"lessThan": "76179961c423cd698080b5e4d5583cf7f4fcdde9",
"versionType": "git"
},
{
"status": "affected",
"version": "1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912",
"lessThan": "fc38c249c622ff5e3011b8845fd49dbfd9289afc",
"versionType": "git"
},
{
"status": "affected",
"version": "1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912",
"lessThan": "938ce0e8422d3793fe30df2ed0e37f6bc0598379",
"versionType": "git"
},
{
"status": "affected",
"version": "1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912",
"lessThan": "2d72afb340657f03f7261e9243b44457a9228ac7",
"versionType": "git"
},
{
"status": "affected",
"version": "594cea2c09f7cd440d1ee1c4547d5bc6a646b0e4",
"versionType": "git"
},
{
"status": "affected",
"version": "5.18.13",
"lessThan": "5.19",
"versionType": "semver"
}
],
"programFiles": [
"include/net/netfilter/nf_conntrack.h",
"net/netfilter/nf_conntrack_core.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.19"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.19",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.147",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.100",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.40",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.15.8",
"versionType": "semver",
"lessThanOrEqual": "6.15.*"
},
{
"status": "unaffected",
"version": "6.16",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/netfilter/nf_conntrack.h",
"net/netfilter/nf_conntrack_core.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-38472
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #30577 · Revision 1
- Added to Heist Feed
- Publisher date