What is CVE-2011-1755?

CVE-2011-1755 is a high-severity vulnerability in Apple Mac OS X, classified under Improper Restriction of Recursive Entity References in DTDs (XML Entity Expansion). CVSS score: 7.5/10. Published 2011-06-21.

How severe is CVE-2011-1755?

High severity. CVSS v3 base score is 7.5 out of 10.

XXE in Apple Mac OS X

CVE-2011-1755

jabberd2 before 2.2.14 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.

Published 2011-06-21 · last modified 2026-06-16.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.037 (89.5th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 89th percentile — 89.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.037 · newest: 0.037 · change: 0.000

Affected products

Apple Mac OS X
Apple Mac OS X Server
Jabberd2
Fedoraproject Fedora — versions 13, 14, 15

Weakness classification (CWE)

CWE-776 — Improper Restriction of Recursive Entity References in DTDs (XML Entity Expansion)

References

exchange.xforce.ibmcloud.com/vulnerabilities/67770 (VDB Entry, Third Party Advisory, vdb-entry)
codex.xiaoka.com/svn/jabberd2/tags/jabberd-2.2.14/ChangeLog (Broken Link)
secunia.com/advisories/44957 (Broken Link, third-party-advisory)
secunia.com/advisories/44787 (Broken Link, Vendor Advisory, third-party-advisory)
lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html (vendor-advisory, Mailing List)
lists.fedoraproject.org/pipermail/package-announce/2011-June/061341.html (vendor-advisory, Mailing List)
www.redhat.com/support/errata/RHSA-2011-0881.html (vendor-advisory, Broken Link)
hermes.opensuse.org/messages/9197650 (vendor-advisory, Broken Link)
bugzilla.redhat.com/show_bug.cgi (Patch, Issue Tracking)
lists.fedoraproject.org/pipermail/package-announce/2011-June/061458.html (vendor-advisory, Mailing List)

Frequently asked questions

What is CVE-2011-1755?: CVE-2011-1755 is a high-severity vulnerability in Apple Mac OS X, classified under Improper Restriction of Recursive Entity References in DTDs (XML Entity Expansion). CVSS score: 7.5/10. Published 2011-06-21.
How severe is CVE-2011-1755?: High severity. CVSS v3 base score is 7.5 out of 10.