Security readout for executives and security teams
Plain-English summary
CVE-2021-43446 is a cross-site scripting issue in ONLYOFFICE’s document editor macro feature. A malicious document or macro could run script in a user’s browser after user interaction, potentially exposing data or changing content within that user’s session. The provided sources do not identify a patch level or active exploitation.
Executive priority
Treat this as a medium-priority web application risk. It is not currently supported as actively exploited in the provided sources, but it can affect user sessions and document integrity. Prioritize environments handling sensitive documents or accepting files from external parties.
Technical view
The CVE describes CWE-79 XSS affecting ONLYOFFICE all versions as of 2021-11-08 via the document editor macros feature. CVSS 3.1 is 6.1: network reachable, low complexity, no privileges, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.
Likely exposure
Exposure is most likely where ONLYOFFICE document editing is deployed and users can open or run documents with macros from untrusted sources. The source bundle lacks precise product, edition, CPE, or fixed-version metadata, so asset validation should focus on actual ONLYOFFICE deployments and macro usage.
Exploitation context
The record is not in CISA KEV, and the provided sources do not prove active exploitation of this CVE. Exploitation requires user interaction and depends on malicious macro content executing in the editor context. The cited Nettitude research indicates ONLYOFFICE has had relevant web attack surface, but should not be treated as proof for this CVE.
Researcher notes
Evidence is limited. The CVE text names ONLYOFFICE and macros, but structured affected fields are n/a and no fixed release is listed. Avoid assuming specific editions, deployment modes, or patch status. Validation should confirm installed product, macro availability, user interaction path, and vendor remediation guidance.
Mitigation direction
- Check ONLYOFFICE vendor guidance for fixed versions or macro-related security settings.
- Upgrade ONLYOFFICE deployments if vendor guidance identifies a corrected release.
- Restrict macro use where business workflows do not require it.
- Limit document editor access to trusted users and trusted network paths.
- Train users to avoid untrusted documents or unexpected macro prompts.
- Monitor document editor activity for suspicious script or macro behavior.
Validation and detection
- Inventory all ONLYOFFICE document editor deployments and exposed entry points.
- Confirm deployed versions against vendor guidance and the 2021-11-08 affected date.
- Verify whether macros are enabled and who can use them.
- Review logs for suspicious document, macro, or editor-session activity.
- Confirm whether compensating controls limit untrusted document handling.
- Track CISA KEV and vendor advisories for exploitation or fix updates.
Public sources used
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-79: 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.
Open ATT&CK lookupCVE-2021-43446 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
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/ONLYOFFICE/serverCVE reference
- https://onlyoffice.com/CVE reference
- https://labs.nettitude.com/blog/exploiting-onlyoffice-web-sockets-for-unauthenticated-remote-code-execution/CVE reference
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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.