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Vulnerabilities

Vulnerability · CVE-2021-3537

A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference.

Published May 14, 2021 · catalog updated Oct 14, 2026 · A vulnerability found in

Check if you run it

No confirmed exploitation is on record for CVE-2021-3537. EPSS is 3.60%. Act only if a listed version of A vulnerability found in is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A vulnerability found in).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
3.60%
Remediation
Advisory link
Affected products
cpe debian/debian linux · cpe fedoraproject/fedora · cpe netapp/active iq unified manager · cpe netapp/hci h410c firmware · cpe oracle/communications cloud native core network function cloud native environment · cpe redhat/enterprise linux

A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe debian/debian linux9.0
  • cpe fedoraproject/fedora33
  • cpe fedoraproject/fedora34
  • cpe netapp/active iq unified managerversion unspecified
  • cpe netapp/hci h410c firmwareversion unspecified
  • cpe oracle/communications cloud native core network function cloud native environment1.10.0
  • cpe redhat/enterprise linux6.0
  • cpe redhat/enterprise linux7.0
  • cpe redhat/enterprise linux8.0
  • cpe redhat/jboss core servicesversion unspecified
  • cpe xmlsoft/libxml2version unspecified

How to fix CVE-2021-3537

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-3537. EPSS is 3.60%. Act only if a listed version of A vulnerability found in is installed.

Which versions are affected?

Compare what you have installed with debian/debian linux 9.0; oracle/communications cloud native core network function cloud native environment 1.10.0; redhat/enterprise linux 6.0; redhat/enterprise linux 7.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-476: NULL Pointer Dereference. EPSS 3.60%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 14, 2021 · NIST NVD

    Detected

    A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

  2. Oct 14, 2026 · NIST NVD

    Updated

    A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

Sources

  • CVE.orgVulnerability recordCVE-2021-3537

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-3537

    30-day exploitation probability 3.6%

    first.org
  • NIST NVDVulnerability recordCVE-2021-3537

    A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the applicat

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.