CVE-2025-71160 (GCVE-0-2025-71160)
Vulnerability from cvelistv5 – Published: 2026-01-23 15:23 – Updated: 2026-01-23 15:23
VLAI?
Title
netfilter: nf_tables: avoid chain re-validation if possible
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: avoid chain re-validation if possible
Hamza Mahfooz reports cpu soft lock-ups in
nft_chain_validate():
watchdog: BUG: soft lockup - CPU#1 stuck for 27s! [iptables-nft-re:37547]
[..]
RIP: 0010:nft_chain_validate+0xcb/0x110 [nf_tables]
[..]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_immediate_validate+0x36/0x50 [nf_tables]
nft_chain_validate+0xc9/0x110 [nf_tables]
nft_table_validate+0x6b/0xb0 [nf_tables]
nf_tables_validate+0x8b/0xa0 [nf_tables]
nf_tables_commit+0x1df/0x1eb0 [nf_tables]
[..]
Currently nf_tables will traverse the entire table (chain graph), starting
from the entry points (base chains), exploring all possible paths
(chain jumps). But there are cases where we could avoid revalidation.
Consider:
1 input -> j2 -> j3
2 input -> j2 -> j3
3 input -> j1 -> j2 -> j3
Then the second rule does not need to revalidate j2, and, by extension j3,
because this was already checked during validation of the first rule.
We need to validate it only for rule 3.
This is needed because chain loop detection also ensures we do not exceed
the jump stack: Just because we know that j2 is cycle free, its last jump
might now exceed the allowed stack size. We also need to update all
reachable chains with the new largest observed call depth.
Care has to be taken to revalidate even if the chain depth won't be an
issue: chain validation also ensures that expressions are not called from
invalid base chains. For example, the masquerade expression can only be
called from NAT postrouting base chains.
Therefore we also need to keep record of the base chain context (type,
hooknum) and revalidate if the chain becomes reachable from a different
hook location.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 53de1e6cde8f9b791d9cf61aa0e7b02cf5bbe8b1
(git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 14fa3d1927f1382f86e3f70a51f26005c8e3cff6 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 09d6074995c186e449979fe6c1b0f1a69cf9bd3b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 8e1a1bc4f5a42747c08130b8242ebebd1210b32f (git) |
||
{
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"programFiles": [
"include/net/netfilter/nf_tables.h",
"net/netfilter/nf_tables_api.c"
],
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"versionType": "git"
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],
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"vendor": "Linux",
"versions": [
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"status": "unaffected",
"version": "6.6.121",
"versionType": "semver"
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{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.66",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "6.18.6",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "6.19-rc2",
"versionType": "original_commit_for_fix"
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"descriptions": [
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: avoid chain re-validation if possible\n\nHamza Mahfooz reports cpu soft lock-ups in\nnft_chain_validate():\n\n watchdog: BUG: soft lockup - CPU#1 stuck for 27s! [iptables-nft-re:37547]\n[..]\n RIP: 0010:nft_chain_validate+0xcb/0x110 [nf_tables]\n[..]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_immediate_validate+0x36/0x50 [nf_tables]\n nft_chain_validate+0xc9/0x110 [nf_tables]\n nft_table_validate+0x6b/0xb0 [nf_tables]\n nf_tables_validate+0x8b/0xa0 [nf_tables]\n nf_tables_commit+0x1df/0x1eb0 [nf_tables]\n[..]\n\nCurrently nf_tables will traverse the entire table (chain graph), starting\nfrom the entry points (base chains), exploring all possible paths\n(chain jumps). But there are cases where we could avoid revalidation.\n\nConsider:\n1 input -\u003e j2 -\u003e j3\n2 input -\u003e j2 -\u003e j3\n3 input -\u003e j1 -\u003e j2 -\u003e j3\n\nThen the second rule does not need to revalidate j2, and, by extension j3,\nbecause this was already checked during validation of the first rule.\nWe need to validate it only for rule 3.\n\nThis is needed because chain loop detection also ensures we do not exceed\nthe jump stack: Just because we know that j2 is cycle free, its last jump\nmight now exceed the allowed stack size. We also need to update all\nreachable chains with the new largest observed call depth.\n\nCare has to be taken to revalidate even if the chain depth won\u0027t be an\nissue: chain validation also ensures that expressions are not called from\ninvalid base chains. For example, the masquerade expression can only be\ncalled from NAT postrouting base chains.\n\nTherefore we also need to keep record of the base chain context (type,\nhooknum) and revalidate if the chain becomes reachable from a different\nhook location."
}
],
"providerMetadata": {
"dateUpdated": "2026-01-23T15:23:58.652Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
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"url": "https://git.kernel.org/stable/c/53de1e6cde8f9b791d9cf61aa0e7b02cf5bbe8b1"
},
{
"url": "https://git.kernel.org/stable/c/14fa3d1927f1382f86e3f70a51f26005c8e3cff6"
},
{
"url": "https://git.kernel.org/stable/c/09d6074995c186e449979fe6c1b0f1a69cf9bd3b"
},
{
"url": "https://git.kernel.org/stable/c/8e1a1bc4f5a42747c08130b8242ebebd1210b32f"
}
],
"title": "netfilter: nf_tables: avoid chain re-validation if possible",
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}
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"cveId": "CVE-2025-71160",
"datePublished": "2026-01-23T15:23:58.652Z",
"dateReserved": "2026-01-13T15:30:19.665Z",
"dateUpdated": "2026-01-23T15:23:58.652Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
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"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2025-71160\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-23T16:15:52.897\",\"lastModified\":\"2026-01-23T16:15:52.897\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnetfilter: nf_tables: avoid chain re-validation if possible\\n\\nHamza Mahfooz reports cpu soft lock-ups in\\nnft_chain_validate():\\n\\n watchdog: BUG: soft lockup - CPU#1 stuck for 27s! [iptables-nft-re:37547]\\n[..]\\n RIP: 0010:nft_chain_validate+0xcb/0x110 [nf_tables]\\n[..]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_immediate_validate+0x36/0x50 [nf_tables]\\n nft_chain_validate+0xc9/0x110 [nf_tables]\\n nft_table_validate+0x6b/0xb0 [nf_tables]\\n nf_tables_validate+0x8b/0xa0 [nf_tables]\\n nf_tables_commit+0x1df/0x1eb0 [nf_tables]\\n[..]\\n\\nCurrently nf_tables will traverse the entire table (chain graph), starting\\nfrom the entry points (base chains), exploring all possible paths\\n(chain jumps). But there are cases where we could avoid revalidation.\\n\\nConsider:\\n1 input -\u003e j2 -\u003e j3\\n2 input -\u003e j2 -\u003e j3\\n3 input -\u003e j1 -\u003e j2 -\u003e j3\\n\\nThen the second rule does not need to revalidate j2, and, by extension j3,\\nbecause this was already checked during validation of the first rule.\\nWe need to validate it only for rule 3.\\n\\nThis is needed because chain loop detection also ensures we do not exceed\\nthe jump stack: Just because we know that j2 is cycle free, its last jump\\nmight now exceed the allowed stack size. We also need to update all\\nreachable chains with the new largest observed call depth.\\n\\nCare has to be taken to revalidate even if the chain depth won\u0027t be an\\nissue: chain validation also ensures that expressions are not called from\\ninvalid base chains. For example, the masquerade expression can only be\\ncalled from NAT postrouting base chains.\\n\\nTherefore we also need to keep record of the base chain context (type,\\nhooknum) and revalidate if the chain becomes reachable from a different\\nhook location.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/09d6074995c186e449979fe6c1b0f1a69cf9bd3b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/14fa3d1927f1382f86e3f70a51f26005c8e3cff6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/53de1e6cde8f9b791d9cf61aa0e7b02cf5bbe8b1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8e1a1bc4f5a42747c08130b8242ebebd1210b32f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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