Security readout for executives and security teams
Plain-English summary
ONLYOFFICE document editor could be abused to make the server fetch and return arbitrary URLs as documents. That matters because an attacker may use a trusted document service to reach internal or sensitive web resources. The bundle does not prove active exploitation or identify a vendor patch.
Executive priority
Treat this as high priority for exposed ONLYOFFICE deployments, especially those with internal network reach. The business risk is data exposure through a trusted collaboration service. Prioritize inventory, exposure reduction, vendor guidance review, and monitoring.
Technical view
CVE-2021-43449 is an SSRF in ONLYOFFICE, described as affecting all versions as of 2021-11-08. The vector is network-accessible with low complexity, no privileges, and user interaction required. The CVSS score is 8.1, with high confidentiality and integrity impact and no availability impact.
Likely exposure
Exposure is most likely where ONLYOFFICE document editor services are internet-facing, embedded in collaboration portals, or able to make outbound requests to internal networks. Exact affected products and versions are not enumerated in the source bundle beyond the 2021-11-08 date statement.
Exploitation context
The bundle cites public research and the CVE record, but CISA KEV status is false and no cited source here confirms active exploitation. The described weakness is SSRF: abusing document fetching behavior to access arbitrary URLs through the server.
Researcher notes
Evidence is incomplete on exact package names, fixed versions, and exploitation in the wild. The strongest source-grounded points are SSRF behavior, broad date-based affected statement, CVSS 8.1, and no KEV listing in the supplied bundle.
Mitigation direction
- Check ONLYOFFICE vendor guidance for fixed versions or configuration changes.
- Inventory and upgrade affected ONLYOFFICE deployments if a vendor fix is available.
- Restrict document editor access to trusted users and trusted network paths.
- Limit outbound network access from the document editor service.
- Monitor for unusual outbound URL fetches from ONLYOFFICE hosts.
Validation and detection
- Identify all ONLYOFFICE deployments and record version/build dates.
- Confirm whether document editor services can reach internal-only URLs.
- Review outbound proxy, firewall, and application logs for anomalous fetches.
- Verify internet exposure and authentication controls around document editor endpoints.
- Track vendor advisories until an affected-version and fix statement is confirmed.
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-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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 lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-43449 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
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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:U/C:H/I:H/A:N2.85.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/ONLYOFFICE/serverCVE reference
- https://www.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.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.