CVE-2026-98591
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bounds check for skb-backed dynptrs The skb_pointer_if_linear() function checks whether a memory region of length len starting at offset off into the skb is in the linear area, and returns a pointer to the region if so. The check currently subtracts between skb_headlen and offset of the check, and since skb_headlen is unsigned the subtraction can underflow. This causes the bounds check to spuriously pass and generate an arbitrary pointer of the form *(skb->data + off). The only user of this helper is currently skb-backed BPF dynptr code. Returning the wrong pointer leads to the dynptr erroneously being backed with invalid memory. Ensure the subtraction cannot underflow, and fail the check if it would. Use u64 arithmetic to also prevent overflow when calculating (skb_headlen(skb) - off) since off is unsigned.
Affected versions
Linux kernel versions
6.6
and later are affected. Fixed in
6.6.158,
6.12.112,
6.18.55,
7.2.9,
7.3
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-98591?
CVE-2026-98591 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.6 onward and has been patched in 6.6.158, 6.12.112, 6.18.55 and others. CVE-2026-98591 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-98591?
Yes. CVE-2026-98591 has been patched. Fixed versions include 6.6.158, 6.12.112, 6.18.55 and others. If you are running Linux kernel 6.6 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-98591 actively exploited?
No. CVE-2026-98591 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.