CVE-2026-89731 (CVSS 7.1)

Description

In the Linux kernel, the following vulnerability has been resolved: cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from the RCRB MMIO block using a readl() loop bounded by sizeof(struct aer_capability_regs). This struct is a software layout and its embedded struct pcie_tlp_log is larger than the on-wire AER capability. As a result the loop reads past the mapped AER register block. The over-read also populates the software-only tail fields including header_log.header_len. An out-of-range header_len passed to pcie_print_tlp_log() can then loop past the header log buffer and cause a second out-of-bounds read. The read was correct when introduced, but struct pcie_tlp_log has since grown (Header Log and TLP Prefix Log sizes, header_len and flit fields), so sizeof(struct aer_capability_regs) no longer matches the physical AER capability. Bound the read to the physical AER registers, header through the 16 byte Header Log. Zero the destination first so the software-only fields are deterministic.

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.05%

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/29458e62d0829cbc99435f3e44fd560f9bbf1da7 https://git.kernel.org/stable/c/8bd3523df1319edc61cd391e695c84a4618516df https://git.kernel.org/stable/c/8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced

Frequently Asked Questions

What is CVE-2026-89731? +

In the Linux kernel, the following vulnerability has been resolved: cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from the RCRB MMIO block using a readl() loop bounded by sizeof(struct aer_capability_regs). This struct is a software layout and its embedded struct pcie_tlp_log is larger than the on-wire AER capability. As a result the loop reads past the mapped AER register block. The over-read also populates the software-only tail fields including header_log.header_len. An out-of-range header_len passed to pcie_print_tlp_log() can then loop past the header log buffer and cause a second out-of-bounds read. The read was correct when introduced, but struct pcie_tlp_log has since grown (Header Log and TLP Prefix Log sizes, header_len and flit fields), so sizeof(struct aer_capability_regs) no longer matches the physical AER capability. Bound the read to the physical AER registers, header through the 16 byte Header Log. Zero the destination first so the software-only fields are deterministic. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-89731? +

CVE-2026-89731 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0016, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-89731? +

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.

CVE-2026-89731