CVE-2011-2516

Exp

Off-by-one error in the XML signature feature in Apache XML Security for C++ 1.6.0, as used in Shibboleth before 2.4.3 and possibly other products, allows remote attackers to cause a denial of service (crash) via a signature using a large RSA key, which triggers a buffer overflow.

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-2011-2516 is rated High Exploit Risk (64.3/100): CVSS Medium severity, with high exploitation likelihood (EPSS 7.30%, 91th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2011-2516

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2011-2516

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 9.83% 7.30% -2.53%
2 2025-03-29 7.30% 9.83% +2.53%
3 2025-03-17 — 7.30% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-2516

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-2011-2516

OS Trackers for CVE-2011-2516

vendor priority summary link
debian low CVE-2011-2516 low priority: Debian including 1 source packages (xml-security-c), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-2516
ubuntu medium CVE-2011-2516 medium priority: Ubuntu including 2 source packages (shibboleth-sp2, xml-security-c), 36 status rows across 18 suites (artful, hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): not-affected 16, ignored 13, released 4, DNE 3. https://ubuntu.com/security/CVE-2011-2516

Affected software / configurations for CVE-2011-2516

Vendor Product Version Raw CPE
apache xml_security_for_c\+\+ 1.6.0 cpe:2.3:a:apache:xml_security_for_c\+\+:1.6.0:*:*:*:*:*:*:*
shibboleth shibboleth-sp <= 2.4.2 cpe:2.3:a:shibboleth:shibboleth-sp:*:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3.1 cpe:2.3:a:shibboleth:shibboleth-sp:1.3.1:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3.2 cpe:2.3:a:shibboleth:shibboleth-sp:1.3.2:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3.3 cpe:2.3:a:shibboleth:shibboleth-sp:1.3.3:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3.4 cpe:2.3:a:shibboleth:shibboleth-sp:1.3.4:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3.5 cpe:2.3:a:shibboleth:shibboleth-sp:1.3.5:*:*:*:*:*:*:*
shibboleth shibboleth-sp 1.3f cpe:2.3:a:shibboleth:shibboleth-sp:1.3f:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.0 cpe:2.3:a:shibboleth:shibboleth-sp:2.0:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.1 cpe:2.3:a:shibboleth:shibboleth-sp:2.1:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.2 cpe:2.3:a:shibboleth:shibboleth-sp:2.2:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.2.1 cpe:2.3:a:shibboleth:shibboleth-sp:2.2.1:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.3 cpe:2.3:a:shibboleth:shibboleth-sp:2.3:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.3.1 cpe:2.3:a:shibboleth:shibboleth-sp:2.3.1:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.4 cpe:2.3:a:shibboleth:shibboleth-sp:2.4:*:*:*:*:*:*:*
shibboleth shibboleth-sp 2.4.1 cpe:2.3:a:shibboleth:shibboleth-sp:2.4.1:*:*:*:*:*:*:*

References for CVE-2011-2516

URL Tags
http://lists.fedoraproject.org/pipermail/package-announce/2011-July/063159.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-July/063229.html
http://santuario.apache.org/secadv/CVE-2011-2516.txt Vendor Advisory
http://secunia.com/advisories/45151 Vendor Advisory
http://secunia.com/advisories/45191 Vendor Advisory
http://secunia.com/advisories/45198
http://secunia.com/advisories/45491
http://shibboleth.internet2.edu/secadv/secadv_20110706.txt Vendor Advisory
http://www.debian.org/security/2011/dsa-2277
http://www.securityfocus.com/archive/1/518756/100/0/threaded
http://www.securityfocus.com/bid/48611
http://www.securitytracker.com/id?1025755
https://exchange.xforce.ibmcloud.com/vulnerabilities/68420
https://issues.apache.org/jira/browse/SANTUARIO-271 Exploit
https://lists.apache.org/thread.html/680e6938b6412e26d5446054fd31de2011d33af11786b989127d1cc3%40%3Ccommits.santuario.apache.org%3E
https://lists.apache.org/thread.html/r1c07a561426ec5579073046ad7f4207cdcef452bb3100abaf908e0cd%40%3Ccommits.santuario.apache.org%3E
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