In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix potential UAF in bpf_netns_link_update_prog
In bpf_netns_link_update_prog, the checks for old_prog and prog type
are currently performed locklessly before acquiring netns_bpf_mutex.
This creates a race condition that can lead to a UAF issue.
If two threads concurrently execute BPF_LINK_UPDATE on the same netns
link, the following execution path can trigger a UAF:
CPU0 CPU1
bpf_netns_link_update_prog
if (old_prog && old_prog != link->prog)
return -EPERM;
bpf_netns_link_update_prog
if (old_prog && old_prog != link->prog)
...
old_prog = xchg(&link->prog, new_prog);
bpf_prog_put(old_prog);
if (new_prog->type != link->prog->type) <-- trigger UAF
Fix this by moving the old_prog and prog->type checks inside the
netns_bpf_mutex critical section. Meanwhile, use guard() to simplify
lock management and avoid all the goto jumping.
bpf: Fix potential UAF in bpf_netns_link_update_prog
In bpf_netns_link_update_prog, the checks for old_prog and prog type
are currently performed locklessly before acquiring netns_bpf_mutex.
This creates a race condition that can lead to a UAF issue.
If two threads concurrently execute BPF_LINK_UPDATE on the same netns
link, the following execution path can trigger a UAF:
CPU0 CPU1
bpf_netns_link_update_prog
if (old_prog && old_prog != link->prog)
return -EPERM;
bpf_netns_link_update_prog
if (old_prog && old_prog != link->prog)
...
old_prog = xchg(&link->prog, new_prog);
bpf_prog_put(old_prog);
if (new_prog->type != link->prog->type) <-- trigger UAF
Fix this by moving the old_prog and prog->type checks inside the
netns_bpf_mutex critical section. Meanwhile, use guard() to simplify
lock management and avoid all the goto jumping.
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 |
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| Linux | Linux | affected |
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Fixes
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Workaround
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References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: bpf: Fix potential UAF in bpf_netns_link_update_prog In bpf_netns_link_update_prog, the checks for old_prog and prog type are currently performed locklessly before acquiring netns_bpf_mutex. This creates a race condition that can lead to a UAF issue. If two threads concurrently execute BPF_LINK_UPDATE on the same netns link, the following execution path can trigger a UAF: CPU0 CPU1 bpf_netns_link_update_prog if (old_prog && old_prog != link->prog) return -EPERM; bpf_netns_link_update_prog if (old_prog && old_prog != link->prog) ... old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); if (new_prog->type != link->prog->type) <-- trigger UAF Fix this by moving the old_prog and prog->type checks inside the netns_bpf_mutex critical section. Meanwhile, use guard() to simplify lock management and avoid all the goto jumping. | |
| Title | bpf: Fix potential UAF in bpf_netns_link_update_prog | |
| 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: 2026-09-17T16:09:26.388Z
Reserved: 2026-09-11T19:38:34.810Z
Link: CVE-2026-90393
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
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