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CVE-2011-2516

23
FAUCET Score

CVE-2011-2516 describes an off-by-one error in the XML signature feature of Apache XML Security for C++ 1.6.0, affecting products like Shibboleth before 2.4.3. This vulnerability allows remote attackers to cause a denial of service (crash) via a buffer overflow triggered by a large RSA key in a signature. With a CVSS score of 5.0 (AV:N/AC:L/Au:N/C:N/I:N/A:P), it is a medium-severity vulnerability that can be exploited remotely with low complexity, resulting in availability impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
1.6.0CPE matchmatch criteria
cpe:2.3:a:apache:xml_security_for_c\+\+:1.6.0:*:*:*:*:*:*:*
<= 2.4.2CPE matchmatch criteria
cpe:2.3:a:shibboleth:shibboleth-sp:*:*:*:*:*:*:*:*
1.3.1CPE matchmatch criteria
cpe:2.3:a:shibboleth:shibboleth-sp:1.3.1:*:*:*:*:*:*:*
1.3.2CPE matchmatch criteria
cpe:2.3:a:shibboleth:shibboleth-sp:1.3.2:*:*:*:*:*:*:*
1.3.3CPE matchmatch criteria
cpe:2.3:a:shibboleth:shibboleth-sp:1.3.3:*:*:*:*:*:*:*

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
7.72%
Probability of exploitation in next 30 days
EPSS Percentile
94.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.0772 is in the 92nd percentile among its peer group of 23,684 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

Remediation records are not available for this CVE.

References

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