Security readout for executives and security teams
Plain-English summary
A malicious LibreOffice document link on Windows could bypass LibreOffice's blocked executable-extension checks and cause Windows ShellExecute to try launching an executable type. Affected versions are LibreOffice 7.1 before 7.1.2 and 7.0 before 7.0.5.
Executive priority
Prioritize remediation where LibreOffice is used on employee Windows endpoints exposed to email attachments, shared documents, or downloaded files. This is not KEV-listed in the provided bundle, but it can support code-launch outcomes if left unpatched.
Technical view
CVE-2021-25631 is a CWE-184 incomplete denylist weakness. Link manipulation could avoid LibreOffice's executable filename-extension denylist while still resolving to a type that ShellExecute attempts to launch on Windows. The public bundle does not provide CVSS scoring.
Likely exposure
Exposure is most likely on Windows endpoints running LibreOffice 7.1.x before 7.1.2 or 7.0.x before 7.0.5, especially where users open untrusted documents or links.
Exploitation context
The provided sources describe a bypass technique and vendor advisory, but do not show CISA KEV listing or confirmed active exploitation. Treat it as user-interaction document risk, not proven widespread exploitation.
Researcher notes
The key condition is denylist mismatch: the visible or parsed link avoids blocked extensions while ShellExecute still treats the target as executable. Evidence is limited to the CVE description, vendor advisory, and Positive Security write-up; no CVSS vector is provided.
Mitigation direction
- Upgrade LibreOffice 7.1 installations to 7.1.2 or later.
- Upgrade LibreOffice 7.0 installations to 7.0.5 or later.
- Review vendor security guidance before accepting untrusted document links.
- Restrict untrusted LibreOffice document handling on Windows endpoints.
- Monitor endpoint controls for LibreOffice launching unexpected executable child processes.
Validation and detection
- Inventory LibreOffice versions across Windows endpoints.
- Confirm no 7.1 builds older than 7.1.2 remain installed.
- Confirm no 7.0 builds older than 7.0.5 remain installed.
- Review EDR telemetry for unusual LibreOffice-to-executable process chains.
- Check document-opening workflows where external files reach users.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-184: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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.
Open ATT&CK lookupCVE-2021-25631 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://positive.security/blog/url-open-rce#open-libreofficeCVE reference · x_refsource_MISC
- https://www.libreoffice.org/about-us/security/advisories/cve-2021-25631/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incomplete List of Disallowed Inputs
Incomplete List of Disallowed Inputs represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.