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CVE-2003-1564

22
FAUCET Score

CVE-2003-1564 describes a denial-of-service vulnerability in libxml2, specifically in versions prior to 2.5.0, where improper recursion detection during entity expansion allows attackers to craft XML documents that consume excessive memory and CPU resources. This vulnerability, known as the "billion laughs attack," carries a CVSS v3.1 score of 6.5 (Medium), indicating it can be exploited remotely with low attack complexity, requiring user interaction, to achieve high availability impact. Despite its age and potential for denial of service, there is no evidence of active exploitation, public exploit code (e.g., Metasploit, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.5.0CPE matchmatch criteria
cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.62%
Probability of exploitation in next 30 days
EPSS Percentile
73.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0162 is in the 86th percentile among its peer group of 26,221 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 2.1Fixed in: libxml2-0:2.4.19-11.ent
View patch

Vendor Advisories (1)

redhatCVE-2003-1564Moderate

libxml2: billion laughs DoS attack

Feb 2, 2003

References

mail.gnome.org / archives/xml/2008-August/msg00034.html
Mailing ListPatch
secunia.com / advisories/31868
Broken Link
reddit.com / r/programming/comments/65843/time_to_upgrade_libxml2
Issue Tracking
redhat.com / support/errata/RHSA-2008-0886.html
Broken Link
stylusstudio.com / xmldev/200302/post20020.html
Broken Link
xmlsoft.org / news.html
Release Notes