CVE-2003-1564

libxml2, possibly before 2.5.0, does not properly detect recursion during entity expansion, which...

6.5 MediumFix available

libxml2, possibly before 2.5.0, does not properly detect recursion during entity expansion, which allows context-dependent attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, aka the "billion laughs attack."

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.62%Up 0.5 points since Feb 4, 2022

What each source reports

NVD Score used 6.5

Record: CVE-2003-1564
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0: 9.3 HighAV:N/AC:M/Au:N/C:C/I:C/A:C
Weakness: CWE-776
Updated: 2026-11-02

CVE List No score

Record: CVE-2003-1564
Updated: 2026-11-02

EUVDEUVD-2003-1554 No score

Record: EUVD-2003-1554
Updated: 2026-11-03

GitHub AdvisoriesGHSA-6wfm-7hqx-39wg 6.5

libxml2, possibly before 2.5.0, does not properly detect recursion during entity expansion, which...

Record: GHSA-6wfm-7hqx-39wg
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-776
Updated: 2026-11-02

Affected products

xmlsoft libxml2

Affected packages

Affected packages
Package	Affected	Fixed
`libxml2` Red Hat:enterprise_linux:2.1::as	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-devel` Red Hat:enterprise_linux:2.1::as	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-python` Red Hat:enterprise_linux:2.1::as	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2` Red Hat:enterprise_linux:2.1::aw	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-devel` Red Hat:enterprise_linux:2.1::aw	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-python` Red Hat:enterprise_linux:2.1::aw	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2` Red Hat:enterprise_linux:2.1::es	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-devel` Red Hat:enterprise_linux:2.1::es	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-python` Red Hat:enterprise_linux:2.1::es	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2` Red Hat:enterprise_linux:2.1::ws	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-devel` Red Hat:enterprise_linux:2.1::ws	before 0:2.4.19-11.ent	0:2.4.19-11.ent
`libxml2-python` Red Hat:enterprise_linux:2.1::ws	before 0:2.4.19-11.ent	0:2.4.19-11.ent

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2003-1564 is a medium vulnerability (CVSS 6.5) in Xmlsoft Libxml2, published December 31, 2003. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.62%, the 76th percentile. Fixed in libxml2 0:2.4.19-11.ent.

References

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