CVE-2026-90210: bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure When bpf_trampoline_update() fails before modify_fentry_multi()/ unregister_fentry_multi() is called, cur_image is unchanged (cur_image == old_image) and ftrace still calls into it. Freeing old_image in that case causes a UAF. Only free old_image when it differs from cur_image.

Affected products

Linux kernel: 7.2 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

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