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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
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Advisories
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Fixes
Solution
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Workaround
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References
History
Sat, 22 Aug 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | bpf: Fix netns reference imbalance in conntrack kfuncs | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-22T15:33:10.262Z
Reserved: 2026-08-15T05:44:03.928Z
Link: CVE-2026-74715
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.