How severe is CVE-2003-1564?

CVE-2003-1564 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2003-1564 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2003-1564?

CVE-2003-1564 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2003-1564?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2003-1564 published?

CVE-2003-1564 was published on 2003-12-31 and last updated on 2026-06-16.

CVE-2003-1564

CVE-2003-1564 is a medium-severity vulnerability in Xmlsoft Libxml2 with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-776.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 9.3
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-776
Affected product: Xmlsoft Libxml2
Published: 2003-12-31
Last modified: 2026-06-16

Description

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."

Frequently asked questions

What is CVE-2003-1564?: 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."
How severe is CVE-2003-1564?: CVE-2003-1564 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2003-1564 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2003-1564?: CVE-2003-1564 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2003-1564?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2003-1564 published?: CVE-2003-1564 was published on 2003-12-31 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

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Other CWE-776 vulnerabilities

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CVE-2013-4335 — Critical (CVSS 9.8): opOpenSocialPlugin 0.8.2.1, > 0.9.9.2, 0.9.13, 1.2.6: Multiple XML External Entity Injection Vulnerabilities
CVE-2021-23926 — Critical (CVSS 9.1): The XML parsers used by XMLBeans up to version 2.6.0 did not set the properties needed to protect the user from…
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Browse all CWE-776 vulnerabilities →