CVE-2026-98626: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Restrict CO-RE poisoning to relocatable instructions CO-RE relocation records can name any instruction offset. When a relocation cannot be resolved, bpf_core_patch_insn() currently poisons its target before checking whether that instruction is a valid relocation target. Malformed metadata can therefore replace jumps, calls, exits, register-source arithmetic, or non-immediate loads instead of failing at the relocation step. Handle poisoning only after the instruction has passed the same class and operand-form checks used for a resolved relocation. Route invalid forms through the existing diagnostic and return a hard error. Keep poisoning supported instructions, including both halves of a plain ldimm64, so an unresolved relocation in dead code remains valid. Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return its status directly from each validated instruction case. This avoids routing the success path through a common label and leaves the helper free to report errors. The shared relocation code applies this restriction to both libbpf and in-kernel CO-RE.

Affected Software

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

Vendor	Product	Versions
Linux	Linux	>= d7a252708dbc950ca2064310217e8b9f85846e2f, < a8c47e62d9aea2d47a09e06c1682c59c21b92449; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < d3219c229d16900cef936adad28633c98946e432; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < f2a24101e89dd0804e717da7c1bd6af513698aa2; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < 2d7d04357c41aa49a5ac658fcc207439f2ad6456; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < 8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319; >= d7a252708dbc950ca2064310217e8b9f85846e2f, < 394ae398337c5f87e567f6cd63b937fc2b2f6ddc
Linux	Linux	5.6

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 19, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98626?

In the Linux kernel, the following vulnerability has been resolved: bpf: Restrict CO-RE poisoning to relocatable instructions CO-RE relocation records can name any instruction offset. When a relocation cannot be resolved, bpf_core_patch_insn() currently poisons its target before checking whether that instruction is a valid relocation target. Malformed metadata can therefore replace jumps, calls, exits, register-source arithmetic, or non-immediate loads instead of failing at the relocation step. Handle poisoning only after the instruction has passed the same class and operand-form checks used for a resolved relocation. Route invalid forms through the existing diagnostic and return a hard error. Keep poisoning supported instructions, including both halves of a plain ldimm64, so an unresolved relocation in dead code remains valid. Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return its status directly from each validated instruction case. This avoids routing the success path through a common label and leaves the helper free to report errors. The shared relocation code applies this restriction to both libbpf and in-kernel CO-RE.

How severe is CVE-2026-98626?

Severity scoring for CVE-2026-98626 is pending analysis.

How do I fix CVE-2026-98626?

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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