CVE-2026-98626

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.

Is your site exposed to CVE-2026-98626?

Run a free security scan — no signup, results in seconds.

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/2d7d04357c41aa49a5ac658fcc207439f2ad6456 https://git.kernel.org/stable/c/394ae398337c5f87e567f6cd63b937fc2b2f6ddc https://git.kernel.org/stable/c/8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319 https://git.kernel.org/stable/c/a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0 https://git.kernel.org/stable/c/a8c47e62d9aea2d47a09e06c1682c59c21b92449 https://git.kernel.org/stable/c/d3219c229d16900cef936adad28633c98946e432 https://git.kernel.org/stable/c/f2a24101e89dd0804e717da7c1bd6af513698aa2

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 do I check if I'm vulnerable to CVE-2026-98626? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.