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Fencer Intel
medium 5.0

CVE-2011-2516 json

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 p…

published 2011-07-11 15 y ago modified 2026-06-16 4 mo ago also EUVD-2011-2501

cvss
5.0
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.7%
EPSS 7.7% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

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.

Patch / fix

  • xml-security-c Debian 14, Debian 13, Debian 12 1.6.1-1

debian advisories DEBIAN-CVE-2011-2516

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-2516 updated cvss 6.8

xml-security-c: Stack-based buffer overflows when creating or verifying XML Signatures with RSA keys of sizes >= 8192 bits

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

7.72% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • issues.apache.org https://issues.apache.org/jira/browse/SANTUARIO-271 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.