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.
Published: 2026-10-18
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Sun, 18 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
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.
Title bpf: Restrict CO-RE poisoning to relocatable instructions
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-18T15:19:47.832Z

Reserved: 2026-09-25T10:25:14.361Z

Link: CVE-2026-98626

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-18T16:17:15.640

Modified: 2026-10-18T16:17:15.640

Link: CVE-2026-98626

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-18T18:30:14Z

Weaknesses

No weakness.