CVE-2006-6931

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."

Published: 2007-01-16 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2006-6931 is rated Moderate Risk (52.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 4.69%). EPSS rose +1.05% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2006-6931

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-09 3.65% 4.69% +1.05%
2 2025-09-04 3.51% 3.65% +0.14%
3 2025-04-02 — 3.51% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2006-6931

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2006-6931

OS Trackers for CVE-2006-6931

vendor priority summary link
gentoo normal CVE-2006-6931: 1 GLSA(s) (200702-03), 1 atom(s) (net-analyzer/snort); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2006-6931
ubuntu low CVE-2006-6931 low priority: Ubuntu including 1 source packages (snort), 9 status rows across 9 suites (dapper, edgy, feisty, gutsy, hardy, intrepid, jaunty, karmic, upstream): released 5, ignored 3, needs-triage 1. https://ubuntu.com/security/CVE-2006-6931

Affected software / configurations for CVE-2006-6931

Vendor Product Version Raw CPE
snort snort <= 2.6.2 cpe:2.3:a:snort:snort:*:*:*:*:*:*:*:*

References for CVE-2006-6931

cvelogic Threat Intelligence