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Fencer Vulns
medium 5.0

CVE-2006-1242 json

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 un…

published 2006-03-15 20 y ago modified 2026-06-16 4 mo ago also EUVD-2006-1246

cvss
5.0
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.5%
EPSS 3.5% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

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.

Patch / fix

  • kernel RHEL 4 2.6.9-42.EL
  • kernel-smp RHEL 4 2.6.9-42.EL
  • kernel-hugemem RHEL 4 2.6.9-42.EL
  • kernel-largesmp RHEL 4 2.6.9-42.EL
  • kernel RHEL 3 2.4.21-47.EL
  • kernel-smp RHEL 3 2.4.21-47.EL
  • kernel-BOOT RHEL 3 2.4.21-47.EL
  • kernel-source RHEL 3 2.4.21-47.EL

red hat advisories RHSA-2006:0575RHSA-2006:0437

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2006-1242 updated

security flaw

  • Red Hat Desktop version 3 kernel 2.4.21-47.EL, kernel-smp 2.4.21-47.EL, kernel-BOOT 2.4.21-47.EL, kernel-source 2.4.21-47.EL, kernel-hugemem 2.4.21-47.EL, kernel-unsupported 2.4.21-47.EL, +2 more Red Hat Enterprise Linux AS version 3 kernel 2.4.21-47.EL, kernel-smp 2.4.21-47.EL, kernel-BOOT 2.4.21-47.EL, kernel-source 2.4.21-47.EL, kernel-hugemem 2.4.21-47.EL, kernel-unsupported 2.4.21-47.EL, +2 more
    fixed: vendor fix RHSA-2006:0437
  • Red Hat Enterprise Linux AS version 4 kernel 2.6.9-42.EL, kernel-smp 2.6.9-42.EL, kernel-hugemem 2.6.9-42.EL, kernel-largesmp 2.6.9-42.EL Red Hat Enterprise Linux Desktop version 4 kernel 2.6.9-42.EL, kernel-smp 2.6.9-42.EL, kernel-hugemem 2.6.9-42.EL, kernel-largesmp 2.6.9-42.EL
    fixed: vendor fix RHSA-2006:0575
  • Red Hat Enterprise Linux ES version 3 kernel 2.4.21-47.EL, kernel-smp 2.4.21-47.EL, kernel-BOOT 2.4.21-47.EL, kernel-source 2.4.21-47.EL, kernel-hugemem 2.4.21-47.EL, kernel-unsupported 2.4.21-47.EL, +2 more
    fixed: vendor fix RHSA-2006:0437
  • Red Hat Enterprise Linux ES version 4 kernel 2.6.9-42.EL, kernel-smp 2.6.9-42.EL, kernel-hugemem 2.6.9-42.EL, kernel-largesmp 2.6.9-42.EL
    fixed: vendor fix RHSA-2006:0575
  • Red Hat Enterprise Linux WS version 3 kernel 2.4.21-47.EL, kernel-smp 2.4.21-47.EL, kernel-BOOT 2.4.21-47.EL, kernel-source 2.4.21-47.EL, kernel-hugemem 2.4.21-47.EL, kernel-unsupported 2.4.21-47.EL, +2 more
    fixed: vendor fix RHSA-2006:0437
  • Red Hat Enterprise Linux WS version 4 kernel 2.6.9-42.EL, kernel-smp 2.6.9-42.EL, kernel-hugemem 2.6.9-42.EL, kernel-largesmp 2.6.9-42.EL
    fixed: vendor fix RHSA-2006:0575

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.54% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.