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CVE-2026-98626

Linux: bpf: Restrict CO-RE poisoning to relocatable instructions

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.21%Chance of exploitation activity in the next 30 days, higher than 10% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2d7d04357c41aa49a5ac658fcc207439f2ad6456Also 8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319, 394ae398337c5f87e567f6cd63b937fc2b2f6ddcCVE List
Published18 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

  • 2d7d04357c41aa49a5ac658fcc207439f2ad6456LinuxCVE List
  • 8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319LinuxCVE List
  • 394ae398337c5f87e567f6cd63b937fc2b2f6ddcLinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 16

  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before a8c47e62d9aea2d47a09e06c1682c59c21b92449CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before d3219c229d16900cef936adad28633c98946e432CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before a0b79cdfcf34b53c85bac2d3cf022fc1342eeca0CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before f2a24101e89dd0804e717da7c1bd6af513698aa2CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before 2d7d04357c41aa49a5ac658fcc207439f2ad6456CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before 8e4cbcca1e0a2fc5e6c8edb68e0cf5f2587f9319CVE List
  • Linuxaffected: d7a252708dbc950ca2064310217e8b9f85846e2f before 394ae398337c5f87e567f6cd63b937fc2b2f6ddcCVE List
  • Linuxaffected: 5.6CVE List
  • Linuxunaffected: all versions before 5.6CVE List
  • Linuxunaffected: 5.15.222 through 5.15.*CVE List
  • Linuxunaffected: 6.1.189 through 6.1.*CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.112 through 6.12.*CVE List
  • Linuxunaffected: 6.18.55 through 6.18.*CVE List
  • Linuxunaffected: 7.2.9 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 7