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Back to active CVEs
High ยท CVSS 8.6CVE-2021-3517

CVE Program ContainerCVE-2021-3517

Answer in brief

CVE-2021-3517 records a High severity (CVSS 8.6) vulnerability in CVE Program Container. The current sources do not mark it as known exploited. The current feed maps n/a/libxml2 (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic), Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published May 19, 2021Updated Oct 14, 2026Source checked Oct 14, 2026First seen by HOL Oct 14, 2026Material review Oct 14, 2026
Upstream Advisory

Key facts

Risk
High ยท CVSS 8.6
Exploitation
Not marked as known exploited
Affected software
4 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps n/a/libxml2 (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic), Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
n/a/libxml2genericlibxml2 2.9.11Not reported
Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5
Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5
Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for n/a/libxml2, Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP.
  2. 2Review the reported fix. Update Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5; Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5; Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    May 19, 2021

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 14, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 14, 2026

Sources and claim methodology

  • Source referencebugzilla.redhat.com
  • Source referencecert-portal.siemens.com
  • Source referencelists.apache.org
  • Source referencelists.apache.org
  • Source referencelists.debian.org
  • Source referencelists.fedoraproject.org
  • Source referencelists.fedoraproject.org
  • Source referencesecurity.gentoo.org
  • Source referencesecurity.netapp.com
  • Source referencesecurity.netapp.com
  • Source referenceoracle.com
  • Source referenceoracle.com
  • Source referenceoracle.com
  • Source referenceoracle.com
Upstream source description

There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker who is able to supply a crafted file to be processed by an application linked with the affected functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to application availability, with some potential impact to confidentiality and integrity if an attacker is able to use memory information to further exploit the application.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Gstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: out-of-bounds write in gst_h266_parser_parse_dci() due to off-by-one array bound checkAlso CWE-787
  • Gstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: heap out-of-bounds write in asfmux due to incorrect utf-16 size calculation for non-bmp charactersAlso CWE-787
  • Gstreamer1-plugins-base: gst-plugins-base: heap buffer overflow via unvalidated gstvideometa plane extents in gst_video_frame_map_id and video_meta_deserializeAlso CWE-787
  • Busybox: busybox: dpkg stale field_start pointer causes out-of-bounds read and status file corruptionAlso CWE-125
  • PeproDev Branches Map <= 3.0.1 - Authenticated (Contributor+) Stored Cross-Site ScriptingSame generic ecosystem
  • WPCode 2.0.0 - 2.3.9 - Unauthenticated Snippet Suppression via Safe Mode BypassSame generic ecosystem

Record context

Vulnerability class
Memory Corruption
EPSS
Not reported
CWE IDs
CWE-787, CWE-125
Source
CVE List V5
Source checked
Oct 14, 2026
References
14 linked sources
Open source record