CVE-2026-98591
N/AIn 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.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 9th percentile
Impact if exploited
—CVSS · not scored
- No impact metrics
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-98591/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-98591/poc.json
References
Technical & other
- https://git.kernel.org/stable/c/1b923538598be768e9f2f258a77a083d00e0c78b
- https://git.kernel.org/stable/c/37877a24758068742fef687a7cf5362360dde1d1
- https://git.kernel.org/stable/c/1196903a27cac5c929c7517e987a8d159f20c5e5
- https://git.kernel.org/stable/c/39ffceaddb10753eac12785dba6ac0673860b4ac
- https://git.kernel.org/stable/c/ed6eec97b534979dcf28b40c389cee57bd6561d4