CVE-2026-72427: Linux Vulnerability (CVSS 7.8)

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix effective prog array index with BPF_F_PREORDER replace_effective_prog() and purge_effective_progs() located the slot in the effective array by walking the program hlist and counting entries linearly. That count does not match the array layout: compute_effective_ progs() places BPF_F_PREORDER programs at the front (ancestor cgroup first, attach order within a cgroup) and the rest after them (descendant cgroup first). So when a preorder program is present, the linear hlist position no longer equals the program's index in the effective array. For replace_effective_prog() (bpf_link_update()) this overwrote the wrong slot, corrupting the effective order. For purge_effective_progs(), it could dummy out a slot belonging to a different program and leave the detached program in the array while bpf_prog_put() drops its reference, i.e. a use-after-free. Fix both by replaying compute_effective_progs()'s placement (including the per-cgroup preorder reversal) in a shared effective_prog_pos() helper. Identify the entry by its struct bpf_prog_list pointer rather than by (prog, link) value, so the lookup resolves to exactly the attachment the syscall selected even when the same bpf_prog is attached to several cgroups in the hierarchy.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.18%

7.3th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= bc8023ef3b11410682e5d4990e05e5bc2d3e1c94, < 525e408c27ae714e538b8c608c3a974df3ab6c92; >= 555c0b713ca83968d3c843cb15485b9ba3367b1b, < 41b4320b84fdafe1ab586b06453d30d50415db59; >= 4b82b181a26cff8bf7adc3a85a88d121d92edeaf, < 9697db03e010391c55ae75192cbdf30c5a72c114; >= 4b82b181a26cff8bf7adc3a85a88d121d92edeaf, < b584f107ab90222bd825dcb4c5977326ff684109; >= 4b82b181a26cff8bf7adc3a85a88d121d92edeaf, < f08aaee3152d0dfc578b3f2586932d82062701dd; 4707ad649cf662add3058bff47430817811b048d; >= 6.6.93, < 6.6.145; >= 6.12.31, < 6.12.97; >= 6.14.9, < 6.15
Linux	Linux	6.15

References

Timeline

Published: Aug 15, 2026
Last Modified: Aug 17, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-72427?

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix effective prog array index with BPF_F_PREORDER replace_effective_prog() and purge_effective_progs() located the slot in the effective array by walking the program hlist and counting entries linearly. That count does not match the array layout: compute_effective_ progs() places BPF_F_PREORDER programs at the front (ancestor cgroup first, attach order within a cgroup) and the rest after them (descendant cgroup first). So when a preorder program is present, the linear hlist position no longer equals the program's index in the effective array. For replace_effective_prog() (bpf_link_update()) this overwrote the wrong slot, corrupting the effective order. For purge_effective_progs(), it could dummy out a slot belonging to a different program and leave the detached program in the array while bpf_prog_put() drops its reference, i.e. a use-after-free. Fix both by replaying compute_effective_progs()'s placement (including the per-cgroup preorder reversal) in a shared effective_prog_pos() helper. Identify the entry by its struct bpf_prog_list pointer rather than by (prog, link) value, so the lookup resolves to exactly the attachment the syscall selected even when the same bpf_prog is attached to several cgroups in the hierarchy.

How severe is CVE-2026-72427?

CVE-2026-72427 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2026-72427?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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