Kernel memory corruption via kdb tab completion
Published Jul 5, 2024 · Updated Aug 5, 2026
Stack-based buffer overflow in Linux kdb allows local users to corrupt kernel memory by tab-completing a nearly full command buffer. In kdb_read(), strncpy() uses the source-buffer length while inserting a completion into cmd_cur, so a mid-line cursor can drive writes past the command buffer. Reaching the flaw requires an enabled kdb console and entry through a keyboard, serial console, or privileged SysRq trigger; exploitation can expose or alter kernel memory or interrupt the system.
Summary
What happened
Stack-based buffer overflow in Linux kdb allows local users to corrupt kernel memory by tab-completing a nearly full command buffer. In kdb_read(), strncpy() uses the source-buffer length while inserting a completion into cmd_cur, so a mid-line cursor can drive writes past the command buffer. Reaching the flaw requires an enabled kdb console and entry through a keyboard, serial console, or privileged SysRq trigger; exploitation can expose or alter kernel memory or interrupt the system.
The record
- CVE
- CVE-2024-39480
- Published
- Jul 5, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-120, CWE-121
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 5, 2024CVE 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
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.6.35
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <107e825cc448b7834b31e8b1b3cf0f57426d46d5
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <33d9c814652b971461d1e30bead6792851c209e7
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <cfdc2fa4db57503bc6d3817240547c8ddc55fa96
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <ddd2972d8e2dee3b33e8121669d55def59f0be8a
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <e9730744bf3af04cda23799029342aa3cddbc454
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <f636a40834d22e5e3fc748f060211879c056cd33
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <f694da720dcf795dc3eb97bf76d220213f76aaa7
- Affected versionversion=5d5314d6795f3c1c0f415348ff8c51f7de042b77 <fb824a99e148ff272a53d71d84122728b5f00992
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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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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