CVE-2011-2943

The irc_msg_who function in msgs.c in the IRC protocol plugin in libpurple 2.8.0 through 2.9.0 in Pidgin before 2.10.0 does not properly validate characters in nicknames, which allows user-assisted remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted nickname that is not properly handled in a WHO response.

Published: 2011-08-29 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-2943 is rated Moderate Risk (47.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.60%). 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-2011-2943

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 2026-06-15 3.96% 3.60% -0.36%
2 2025-03-30 8.82% 3.96% -4.86%
3 2025-03-29 — 8.82% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-2943

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-2011-2943

OS Trackers for CVE-2011-2943

vendor priority summary link
debian not yet assigned CVE-2011-2943 not yet assigned priority: Debian including 1 source packages (pidgin), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-2943
redhat low — https://access.redhat.com/security/cve/CVE-2011-2943
ubuntu low CVE-2011-2943 low priority: Ubuntu including 1 source packages (pidgin), 6 status rows across 6 suites (hardy, lucid, maverick, natty, oneiric, upstream): not-affected 4, ignored 1, released 1. https://ubuntu.com/security/CVE-2011-2943

NVD evaluator notes for CVE-2011-2943

Comment: Per: http://cwe.mitre.org/data/definitions/476.html 'CWE-476: NULL Pointer Dereference'

Affected software / configurations for CVE-2011-2943

Vendor Product Version Raw CPE
pidgin libpurple 2.8.0 cpe:2.3:a:pidgin:libpurple:2.8.0:*:*:*:*:*:*:*
pidgin libpurple 2.9.0 cpe:2.3:a:pidgin:libpurple:2.9.0:*:*:*:*:*:*:*
pidgin pidgin <= 2.9.0 cpe:2.3:a:pidgin:pidgin:*:*:*:*:*:*:*:*
pidgin pidgin 2.0.0 cpe:2.3:a:pidgin:pidgin:2.0.0:*:*:*:*:*:*:*
pidgin pidgin 2.0.1 cpe:2.3:a:pidgin:pidgin:2.0.1:*:*:*:*:*:*:*
pidgin pidgin 2.0.2 cpe:2.3:a:pidgin:pidgin:2.0.2:*:*:*:*:*:*:*
pidgin pidgin 2.1.0 cpe:2.3:a:pidgin:pidgin:2.1.0:*:*:*:*:*:*:*
pidgin pidgin 2.1.1 cpe:2.3:a:pidgin:pidgin:2.1.1:*:*:*:*:*:*:*
pidgin pidgin 2.2.0 cpe:2.3:a:pidgin:pidgin:2.2.0:*:*:*:*:*:*:*
pidgin pidgin 2.2.1 cpe:2.3:a:pidgin:pidgin:2.2.1:*:*:*:*:*:*:*
pidgin pidgin 2.2.2 cpe:2.3:a:pidgin:pidgin:2.2.2:*:*:*:*:*:*:*
pidgin pidgin 2.3.0 cpe:2.3:a:pidgin:pidgin:2.3.0:*:*:*:*:*:*:*
pidgin pidgin 2.3.1 cpe:2.3:a:pidgin:pidgin:2.3.1:*:*:*:*:*:*:*
pidgin pidgin 2.4.0 cpe:2.3:a:pidgin:pidgin:2.4.0:*:*:*:*:*:*:*
pidgin pidgin 2.4.1 cpe:2.3:a:pidgin:pidgin:2.4.1:*:*:*:*:*:*:*
pidgin pidgin 2.4.2 cpe:2.3:a:pidgin:pidgin:2.4.2:*:*:*:*:*:*:*
pidgin pidgin 2.4.3 cpe:2.3:a:pidgin:pidgin:2.4.3:*:*:*:*:*:*:*
pidgin pidgin 2.5.0 cpe:2.3:a:pidgin:pidgin:2.5.0:*:*:*:*:*:*:*
pidgin pidgin 2.5.1 cpe:2.3:a:pidgin:pidgin:2.5.1:*:*:*:*:*:*:*
pidgin pidgin 2.5.2 cpe:2.3:a:pidgin:pidgin:2.5.2:*:*:*:*:*:*:*
pidgin pidgin 2.5.3 cpe:2.3:a:pidgin:pidgin:2.5.3:*:*:*:*:*:*:*
pidgin pidgin 2.5.4 cpe:2.3:a:pidgin:pidgin:2.5.4:*:*:*:*:*:*:*
pidgin pidgin 2.5.5 cpe:2.3:a:pidgin:pidgin:2.5.5:*:*:*:*:*:*:*
pidgin pidgin 2.5.6 cpe:2.3:a:pidgin:pidgin:2.5.6:*:*:*:*:*:*:*
pidgin pidgin 2.5.7 cpe:2.3:a:pidgin:pidgin:2.5.7:*:*:*:*:*:*:*
pidgin pidgin 2.5.8 cpe:2.3:a:pidgin:pidgin:2.5.8:*:*:*:*:*:*:*
pidgin pidgin 2.5.9 cpe:2.3:a:pidgin:pidgin:2.5.9:*:*:*:*:*:*:*
pidgin pidgin 2.6.0 cpe:2.3:a:pidgin:pidgin:2.6.0:*:*:*:*:*:*:*
pidgin pidgin 2.6.1 cpe:2.3:a:pidgin:pidgin:2.6.1:*:*:*:*:*:*:*
pidgin pidgin 2.6.2 cpe:2.3:a:pidgin:pidgin:2.6.2:*:*:*:*:*:*:*
pidgin pidgin 2.6.4 cpe:2.3:a:pidgin:pidgin:2.6.4:*:*:*:*:*:*:*
pidgin pidgin 2.6.5 cpe:2.3:a:pidgin:pidgin:2.6.5:*:*:*:*:*:*:*
pidgin pidgin 2.6.6 cpe:2.3:a:pidgin:pidgin:2.6.6:*:*:*:*:*:*:*
pidgin pidgin 2.7.0 cpe:2.3:a:pidgin:pidgin:2.7.0:*:*:*:*:*:*:*
pidgin pidgin 2.7.1 cpe:2.3:a:pidgin:pidgin:2.7.1:*:*:*:*:*:*:*
pidgin pidgin 2.7.2 cpe:2.3:a:pidgin:pidgin:2.7.2:*:*:*:*:*:*:*
pidgin pidgin 2.7.3 cpe:2.3:a:pidgin:pidgin:2.7.3:*:*:*:*:*:*:*
pidgin pidgin 2.7.4 cpe:2.3:a:pidgin:pidgin:2.7.4:*:*:*:*:*:*:*
pidgin pidgin 2.7.5 cpe:2.3:a:pidgin:pidgin:2.7.5:*:*:*:*:*:*:*
pidgin pidgin 2.7.6 cpe:2.3:a:pidgin:pidgin:2.7.6:*:*:*:*:*:*:*
pidgin pidgin 2.7.7 cpe:2.3:a:pidgin:pidgin:2.7.7:*:*:*:*:*:*:*
pidgin pidgin 2.7.8 cpe:2.3:a:pidgin:pidgin:2.7.8:*:*:*:*:*:*:*
pidgin pidgin 2.7.9 cpe:2.3:a:pidgin:pidgin:2.7.9:*:*:*:*:*:*:*
pidgin pidgin 2.7.10 cpe:2.3:a:pidgin:pidgin:2.7.10:*:*:*:*:*:*:*
pidgin pidgin 2.7.11 cpe:2.3:a:pidgin:pidgin:2.7.11:*:*:*:*:*:*:*
pidgin pidgin 2.8.0 cpe:2.3:a:pidgin:pidgin:2.8.0:*:*:*:*:*:*:*

References for CVE-2011-2943

URL Tags
http://developer.pidgin.im/viewmtn/revision/diff/5749f9193063800d27bef75c2388f6f9cc2f7f37/with/5c2dba4a7e2e76b76e7f472b88953a4316706d43/libpurple/protocols/irc/msgs.c Patch
http://developer.pidgin.im/viewmtn/revision/info/5c2dba4a7e2e76b76e7f472b88953a4316706d43 Patch
http://pidgin.im/news/security/?id=53 Patch Vendor Advisory
http://secunia.com/advisories/45663 Vendor Advisory
http://secunia.com/advisories/45916
http://securitytracker.com/id?1025961
http://www.openwall.com/lists/oss-security/2011/08/20/2
http://www.openwall.com/lists/oss-security/2011/08/22/2
http://www.securityfocus.com/bid/49268
https://bugzilla.redhat.com/show_bug.cgi?id=722939
https://exchange.xforce.ibmcloud.com/vulnerabilities/69340
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18005
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