CVE-2011-1951

lib/logmatcher.c in Balabit syslog-ng before 3.2.4, when the global flag is set and when using PCRE 8.12 and possibly other versions, allows remote attackers to cause a denial of service (memory consumption) via a message that does not match a regular expression.

Published: 2011-07-11 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-1951 is rated Moderate Risk (45/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.55%). 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-2011-1951

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 2025-03-30 1.67% 1.55% -0.12%
2 2025-03-29 1.55% 1.67% +0.12%
3 2025-03-17 — 1.55% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-1951

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2011-1951

OS Trackers for CVE-2011-1951

vendor priority summary link
debian low CVE-2011-1951 low priority: Debian including 1 source packages (syslog-ng), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-1951
gentoo high CVE-2011-1951: 1 GLSA(s) (201412-09), 25 atom(s) (app-admin/syslog-ng, app-misc/ca-certificates, …); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2011-1951
ubuntu low CVE-2011-1951 low priority: Ubuntu including 1 source packages (syslog-ng), 10 status rows across 10 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, upstream): not-affected 5, ignored 4, needs-triage 1. https://ubuntu.com/security/CVE-2011-1951

Affected software / configurations for CVE-2011-1951

Vendor Product Version Raw CPE
oneidentity syslog-ng < 3.2.4 cpe:2.3:a:oneidentity:syslog-ng:*:*:*:*:*:*:*:*

References for CVE-2011-1951

cvelogic Threat Intelligence