bpf: Fix netns reference imbalance in conntrack kfuncs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74715
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:46 UTC
Updated2026-10-21 13:19:49 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001730000 probability, percentile 0.063210000 (date 2026-10-16)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected aed8ee7feb44b6537af1e0b4f03365d42928be38 fb22bedf0c4f4f05bfa6e4a7ec0fd97bbdff9ce8 git Not specified
CNA Linux Linux affected aed8ee7feb44b6537af1e0b4f03365d42928be38 41731d4290400cb898f15f049ae4018d45415e69 git Not specified
CNA Linux Linux affected aed8ee7feb44b6537af1e0b4f03365d42928be38 4af94462c0ca2187a02a1a6641020ae888c74d5c git Not specified
CNA Linux Linux affected aed8ee7feb44b6537af1e0b4f03365d42928be38 e5e060eb63d10b41ab60fd955649479d99b38210 git Not specified
CNA Linux Linux affected aed8ee7feb44b6537af1e0b4f03365d42928be38 fdeba03fea78407a8c52faa99177c9f7f29f90eb git Not specified
CNA Linux Linux affected 6.0 Not specified
CNA Linux Linux unaffected 6.0 semver Not specified
CNA Linux Linux unaffected 6.6.160 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.114 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.57 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/41731d4290400cb898f15f049ae4018d45415e69 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fb22bedf0c4f4f05bfa6e4a7ec0fd97bbdff9ce8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4af94462c0ca2187a02a1a6641020ae888c74d5c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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