Kernel crash via unchecked response-buffer length
Published Sep 17, 2026 · Updated Sep 17, 2026
Unchecked output sizing in Linux 6.15 CXL Set Features allows local users to crash the kernel via a crafted fwctl request. The cxlctl_set_feature() handler allocates the caller's fwctl_rpc.out_len without checking response-header capacity; zero returns ZERO_SIZE_PTR, and writing rpc_out->size dereferences that poison pointer. Reachability requires access to a CXL fwctl device exposing writable features; Amazon assesses exploitation as requiring high privileges.
Summary
What happened
Unchecked output sizing in Linux 6.15 CXL Set Features allows local users to crash the kernel via a crafted fwctl request. The cxlctl_set_feature() handler allocates the caller's fwctl_rpc.out_len without checking response-header capacity; zero returns ZERO_SIZE_PTR, and writing rpc_out->size dereferences that poison pointer. Reachability requires access to a CXL fwctl device exposing writable features; Amazon assesses exploitation as requiring high privileges.
The record
- CVE
- CVE-2026-93078
- Published
- Sep 17, 2026
- Updated
- Sep 17, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 17, 2026CVE publishedPublication date reported by the CVE source.
- Sep 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.15
- Affected versionversion=eb5dfcb9e36d0e46089fec777d911313c1876fa3 <1281dc84c81577b51e2b61c24617c9f44b2cdb99
- Affected versionversion=eb5dfcb9e36d0e46089fec777d911313c1876fa3 <16b7c99eff030c6ea11ca24efa4b9f989cc74093
- Affected versionversion=eb5dfcb9e36d0e46089fec777d911313c1876fa3 <cde18d6c1d913a67ab0afd3d9475ece4be79da50
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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