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CVE-2011-4539

25
FAUCET Score

CVE-2011-4539 describes a denial-of-service vulnerability in ISC DHCP versions 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4, affecting various Canonical, Debian, and ISC DHCP deployments. This flaw allows an unauthenticated remote attacker to crash the dhcpd daemon by sending a specially crafted request packet that exploits improper handling of regular expressions in the dhcpd.conf file. With a CVSS score of 5.0 (AV:N/AC:L/Au:N/C:N/I:N/A:P), it indicates a low complexity attack with no authentication required, leading to a partial availability impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
4.0CPE matchmatch criteria
cpe:2.3:a:isc:dhcp:4.0:*:*:*:*:*:*:*
4.0.0CPE matchmatch criteria
cpe:2.3:a:isc:dhcp:4.0.0:*:*:*:*:*:*:*
4.0.1CPE matchmatch criteria
cpe:2.3:a:isc:dhcp:4.0.1:-:*:*:*:*:*:*
4.0.1CPE matchmatch criteria
cpe:2.3:a:isc:dhcp:4.0.1:b1:*:*:*:*:*:*
4.0.1CPE matchmatch criteria
cpe:2.3:a:isc:dhcp:4.0.1:rc1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

5.0MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/A:P

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
2.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
14.94%
Probability of exploitation in next 30 days
EPSS Percentile
96.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.1494 is in the 96th percentile among its peer group of 23,701 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: dhcp-12:4.1.1-25.P1.el6_2.1
View patch

Vendor Advisories (1)

redhatCVE-2011-4539Moderate

dhcp: DoS due to processing certain regular expressions

Dec 7, 2011

References

lists.fedoraproject.org / pipermail/package-announce/2011-December/070980.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2012-January/071549.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-updates/2011-12/msg00006.html
Mailing ListThird Party Advisory
secunia.com / advisories/47153
Third Party Advisory
secunia.com / advisories/47178
Third Party Advisory
security.gentoo.org / glsa/glsa-201301-06.xml
Third Party Advisory
exchange.xforce.ibmcloud.com / vulnerabilities/71680
Third Party AdvisoryVDB Entry
isc.org / software/dhcp/advisories/cve-2011-4539
Vendor Advisory
debian.org / security/2012/dsa-2519
Third Party Advisory
mandriva.com / security/advisories
Third Party Advisory
securityfocus.com / bid/50971
Third Party AdvisoryVDB Entry
securitytracker.com / id
Third Party AdvisoryVDB Entry
ubuntu.com / usn/USN-1309-1
Third Party Advisory