Linux Kernel up to 7.2.8/7.3-rc4 BPF regsafe out-of-bounds

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.2.8/7.3-rc4. This issue affects the function regsafe of the component BPF. The manipulation leads to out-of-bounds. This vulnerability is traded as CVE-2026-98627. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.2.8/7.3-rc4. This issue affects the function regsafe of the component BPF. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: bpf: Preserve packet pointer class displacement in regsafe() regsafe() maps packet pointer IDs between states and checks that each current register range is a subset of the corresponding explored register range. It does not, however, preserve the displacement between registers that share a packet pointer ID. This is unsound because packet range is shared by ID. A bounds check on one class member updates every member, and a later access can consume the range through another member. Commit 022ac0750883 ("bpf: use reg->var_off instead of reg->off for pointers") folded the fixed pointer offset into r64 and removed the old off equality check, so two individually narrower registers can prune even when their displacement has changed. The explored path can then license an out-of-bounds packet access on the pruned path. Require matching range bases for packet pointers with an ID. Together with the existing ID mapping, this preserves the displacement between members of each packet-pointer class without adding per-ID state. Packet pointers without an ID remain unaffected.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-98627 since 09/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are needed for exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/18/2026).

Upgrading to version 7.2.9 or 7.3-rc5 eliminates this vulnerability. Applying the patch 091b40845bd3cf96791171ca95113e9184ccb596/fd16449a9b3b31a8f18944c2f0e29e4e218ca2cf is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.2.8
• 7.3-rc1
• 7.3-rc2
• 7.3-rc3
• 7.3-rc4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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