CVE-2026-74715 (GCVE-0-2026-74715)
Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-22 15:33
VLAI
EPSS
VEX
Title
bpf: Fix netns reference imbalance in conntrack kfuncs
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix netns reference imbalance in conntrack kfuncs
The opts argument of the BPF conntrack kfuncs can point to a shared
map value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read
opts->netns_id separately when acquiring and releasing the network
namespace reference.
The reference imbalance can occur as follows:
CPU 0 CPU 1
read opts->netns_id (-1)
skip get_net_ns_by_id()
write opts->netns_id (id)
read opts->netns_id (id)
put_net(net) /* no matching get */
The reverse transition leaks the reference. Repeating the unmatched put
can destroy a live namespace and crash later users.
The kernel reported:
Oops: general protection fault, probably for non-canonical address
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700
Call Trace:
__sys_bpf+0x1662/0x50c0
__x64_sys_bpf+0x73/0xb0
do_syscall_64+0xf9/0x540
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Kernel panic - not syncing: Fatal exception
Snapshot every input field of opts with READ_ONCE() before validating or
using it. The netns_id snapshot keeps the namespace get/put pair
balanced, while the other snapshots keep the remaining options from
changing partway through an invocation. The individual reads can still
observe an inconsistent combination during a concurrent update, but each
selected field value remains stable for that invocation.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
aed8ee7feb44b6537af1e0b4f03365d42928be38 , < e5e060eb63d10b41ab60fd955649479d99b38210
(git)
Affected: aed8ee7feb44b6537af1e0b4f03365d42928be38 , < fdeba03fea78407a8c52faa99177c9f7f29f90eb (git) |
guessed | |
| Linux | Linux |
Affected:
6.0
Unaffected: 0 , < 6.0 (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
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"programFiles": [
"net/netfilter/nf_conntrack_bpf.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
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"vendor": "Linux",
"versions": [
{
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"version": "6.0"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.9",
"versionStartIncluding": "6.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix netns reference imbalance in conntrack kfuncs\n\nThe opts argument of the BPF conntrack kfuncs can point to a shared\nmap value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\nopts-\u003enetns_id separately when acquiring and releasing the network\nnamespace reference.\n\nThe reference imbalance can occur as follows:\n\n CPU 0 CPU 1\n read opts-\u003enetns_id (-1)\n skip get_net_ns_by_id()\n write opts-\u003enetns_id (id)\n read opts-\u003enetns_id (id)\n put_net(net) /* no matching get */\n\nThe reverse transition leaks the reference. Repeating the unmatched put\ncan destroy a live namespace and crash later users.\n\nThe kernel reported:\n\n Oops: general protection fault, probably for non-canonical address\n KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\n RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\n Call Trace:\n __sys_bpf+0x1662/0x50c0\n __x64_sys_bpf+0x73/0xb0\n do_syscall_64+0xf9/0x540\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n Kernel panic - not syncing: Fatal exception\n\nSnapshot every input field of opts with READ_ONCE() before validating or\nusing it. The netns_id snapshot keeps the namespace get/put pair\nbalanced, while the other snapshots keep the remaining options from\nchanging partway through an invocation. The individual reads can still\nobserve an inconsistent combination during a concurrent update, but each\nselected field value remains stable for that invocation."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-22T15:33:10.262Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210"
},
{
"url": "https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb"
}
],
"title": "bpf: Fix netns reference imbalance in conntrack kfuncs",
"x_generator": {
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}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74715",
"datePublished": "2026-08-22T15:33:10.262Z",
"dateReserved": "2026-08-15T05:44:03.928Z",
"dateUpdated": "2026-08-22T15:33:10.262Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-74715\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:46.313\",\"lastModified\":\"2026-08-22T16:16:46.313\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: Fix netns reference imbalance in conntrack kfuncs\\n\\nThe opts argument of the BPF conntrack kfuncs can point to a shared\\nmap value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\\nopts-\u003enetns_id separately when acquiring and releasing the network\\nnamespace reference.\\n\\nThe reference imbalance can occur as follows:\\n\\n CPU 0 CPU 1\\n read opts-\u003enetns_id (-1)\\n skip get_net_ns_by_id()\\n write opts-\u003enetns_id (id)\\n read opts-\u003enetns_id (id)\\n put_net(net) /* no matching get */\\n\\nThe reverse transition leaks the reference. Repeating the unmatched put\\ncan destroy a live namespace and crash later users.\\n\\nThe kernel reported:\\n\\n Oops: general protection fault, probably for non-canonical address\\n KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\\n RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\\n Call Trace:\\n __sys_bpf+0x1662/0x50c0\\n __x64_sys_bpf+0x73/0xb0\\n do_syscall_64+0xf9/0x540\\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\\n Kernel panic - not syncing: Fatal exception\\n\\nSnapshot every input field of opts with READ_ONCE() before validating or\\nusing it. The netns_id snapshot keeps the namespace get/put pair\\nbalanced, while the other snapshots keep the remaining options from\\nchanging partway through an invocation. The individual reads can still\\nobserve an inconsistent combination during a concurrent update, but each\\nselected field value remains stable for that invocation.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/netfilter/nf_conntrack_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"aed8ee7feb44b6537af1e0b4f03365d42928be38\",\"lessThan\":\"e5e060eb63d10b41ab60fd955649479d99b38210\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"aed8ee7feb44b6537af1e0b4f03365d42928be38\",\"lessThan\":\"fdeba03fea78407a8c52faa99177c9f7f29f90eb\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/netfilter/nf_conntrack_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
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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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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