Local privilege escalation via negative BAR index
Published Nov 12, 2025 · Updated Aug 5, 2026
Array underflow in Linux kernel 6.17 through 6.17.2 allows local users to gain kernel privileges via a negative PCITEST_BAR index. pci_endpoint_test_ioctl() accepts a signed negative BAR number because its upper-bound check omits a lower-bound check, then pci_endpoint_test_bar() indexes arrays below their start. Access to /dev/pci-endpoint-test.N is required; one ioctl can drive out-of-bounds reads and writes that disclose or corrupt kernel memory and panic the host.
Summary
What happened
Array underflow in Linux kernel 6.17 through 6.17.2 allows local users to gain kernel privileges via a negative PCITEST_BAR index. pci_endpoint_test_ioctl() accepts a signed negative BAR number because its upper-bound check omits a lower-bound check, then pci_endpoint_test_bar() indexes arrays below their start. Access to /dev/pci-endpoint-test.N is required; one ioctl can drive out-of-bounds reads and writes that disclose or corrupt kernel memory and panic the host.
The record
- CVE
- CVE-2025-40117
- Published
- Nov 12, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 12, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.17
- Affected versionversion=eefb83790a0dda112d1755e4f5e213738d717e76 <1ad82f9db13d85667366044acdfb02009d576c5a
- Affected versionversion=eefb83790a0dda112d1755e4f5e213738d717e76 <6df3687922570f753574c40b35e83b26b32292d0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo