Description
The (1) IPv4 and (2) IPv6 implementations in the Linux kernel before 3.1 use a modified MD4 algorithm to generate sequence numbers and Fragment Identification values, which makes it easier for remote attackers to cause a denial of service (disrupted networking) or hijack network sessions by predicting these values and sending crafted packets.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | linux-2.6 | 2.6.32-35squeeze1 | DSA-2303-1 |
| Debian 5.0 | linux-2.6 | 2.6.26-26lenny4 | DSA-2310-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | perf +14 | 2.6.32-131.21.1.el6 | RHSA-2011:1465 |
| RHEL 5 | kernel +11 | 2.6.18-274.7.1.el5 | RHSA-2011:1386 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5.6 EUS | kernel +12 | 2.6.18-238.28.1.el5 | RHSA-2011:1419 |
| Red Hat MRG 2 | kernel-rt +10 | 2.6.33.9-rt31.79.el6rt | RHSA-2012:0010 |
Advisories 6
- RHSA-2012:0010 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2011:1419 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2011:1386 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-2303-1 linux-2.6 - several issues Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-2310-1 linux-2.6 - several issues Debian Security (DSA / DLA) · Mar 9, 2026
- RHSA-2011:1465 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Nov 22, 2025
References
- https://github.com/torvalds/linux/commit/bc0b96b54a21246e377122d54569eef71cec535f
- [oss-security] 20110823 Re: CVE request: kernel: change in how tcp seq numbers are generated mailing-list
- https://github.com/torvalds/linux/commit/6e5714eaf77d79ae1c8b47e3e040ff5411b717ec
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=6e5714eaf77d79ae1c8b47e3e040ff5411b717ec
- https://bugzilla.redhat.com/show_bug.cgi?id=732658
- http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.1
- HPSBGN02970 vendor-advisory
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=bc0b96b54a21246e377122d54569eef71cec535f
- https://support.f5.com/csp/article/K15301?utm_source=f5support&%3Butm_medium=RSS