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CVE Record

CVE-2019-9853: Insufficient URL decoding flaw in categorizing macro location

LibreOffice documents can contain macros. The execution of those macros is controlled by the document security settings, typically execution of macros are blocked by default. A URL decoding flaw existed in how the urls to the macros within the document were processed and categorized, resulting in the possibility to construct a document where macro execution bypassed the security settings. The documents were correctly detected as containing macros, and prompted the user to their existence within the documents, but macros within the document were subsequently not controlled by the security settings allowing arbitrary macro execution This issue affects: LibreOffice 6.2 series versions prior to 6.2.7; LibreOffice 6.3 series versions prior to 6.3.1.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malicious LibreOffice document could make macros run even when macro security settings should block them. The document may still warn that macros exist, but the vulnerable handling can leave the macros outside normal enforcement. This is mainly a workstation and document-processing risk.

Executive priority

Prioritize remediation where LibreOffice handles files from email, uploads, partners, or customers. The issue undermines macro controls, so it fits phishing and malicious-document risk even without confirmed active exploitation in the provided sources.

Technical view

CVE-2019-9853 is an insufficient URL decoding issue in LibreOffice macro URL processing and categorization. Crafted macro locations could bypass security setting enforcement, enabling arbitrary macro execution. Affected versions are LibreOffice 6.2 before 6.2.7 and 6.3 before 6.3.1.

Likely exposure

Exposure is most likely on endpoints, VDI images, or servers that open or convert untrusted documents using vulnerable LibreOffice 6.2 or 6.3 builds.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. Practical exploitation would depend on getting a user or automated document workflow to open a crafted macro-bearing file.

Researcher notes

The important behavior is not macro detection failure; sources state documents were detected as containing macros. The flaw was in subsequent categorization and control of macro URLs after insufficient decoding. Evidence names LibreOffice only; do not infer broader product impact from related mailing-list references alone.

Mitigation direction

  • Upgrade LibreOffice 6.2 to 6.2.7 or later.
  • Upgrade LibreOffice 6.3 to 6.3.1 or later.
  • Confirm Linux distribution packages include the Debian, Fedora, or vendor security updates.
  • Restrict automated document conversion of untrusted files until patched.
  • Follow current vendor guidance for any downstream packaged builds.

Validation and detection

  • Inventory LibreOffice versions across endpoints and document-processing servers.
  • Flag 6.2 versions earlier than 6.2.7 as vulnerable.
  • Flag 6.3 versions earlier than 6.3.1 as vulnerable.
  • Check package changelogs or advisories for CVE-2019-9853 backports.
  • Review document workflows that process externally supplied office files.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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cwe · medium confidence lookup

CWE-116: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2019-9853 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
15Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Document FoundationLibreOffice6.2 series, 6.3 seriesListed
Weakness

CWE details

CWE-116

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-116 · source CWE mapping

Improper Encoding or Escaping of Output

Improper Encoding or Escaping of Output represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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