What is CVE-2009-3560?

CVE-2009-3560 is a vulnerability in Apache HTTP Server, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. Published 2009-12-04.

Is CVE-2009-3560 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Apache HTTP Server

CVE-2009-3560

The big2_toUtf8 function in lib/xmltok.c in libexpat in Expat 2.0.1, as used in the XML-Twig module for Perl, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with malformed UTF-8 sequences that trigger a buffer over-read, related to the doProlog function in lib/xmlparse.c, a different vulnerability than CVE-2009-2625 and CVE-2009-3720.

Vulnerability class: Buffer Overflow

Published 2009-12-04 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 5.0 (Medium). Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.243 (97.8th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.243 · newest: 0.243 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

Public proof-of-concept exploits

References

expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmlparse.c (Permissions Required)
slackware.com/security/viewer.php (vendor-advisory, Mailing List, Third Party Advisory)
www.redhat.com/archives/fedora-package-announce/2009-December/msg00370.html (vendor-advisory, Mailing List, Third Party Advisory)
secunia.com/advisories/38832 (Broken Link, third-party-advisory)
www.securitytracker.com/id (VDB Entry, Third Party Advisory, vdb-entry)
www.ubuntu.com/usn/USN-890-1 (vendor-advisory, VDB Entry, Third Party Advisory)
secunia.com/advisories/38794 (Broken Link, third-party-advisory)
lists.vmware.com/pipermail/security-announce/2010/000082.html (mailing-list, Broken Link)
www.vupen.com/english/advisories/2010/1107 (vdb-entry, Broken Link)
www.debian.org/security/2009/dsa-1953 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2009-3560?: CVE-2009-3560 is a vulnerability in Apache HTTP Server, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. Published 2009-12-04.
Is CVE-2009-3560 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.