Security readout for executives and security teams
Plain-English summary
Nextcloud Richdocuments had insufficient rate limiting on an OCS endpoint. An unauthenticated network attacker may have been able to repeatedly probe for potentially valid share tokens, creating an information-disclosure risk. The advisory names fixed Richdocuments versions and recommends disabling the app if upgrading is not possible.
Executive priority
Treat as a medium-priority confidentiality issue. It is not supported as actively exploited in the provided evidence, but internet-facing collaboration platforms can expose sensitive sharing workflows. Patch during the next normal security maintenance window, sooner for externally exposed or heavily shared environments.
Technical view
CVE-2021-37629 is a CWE-200 information exposure issue in Nextcloud Richdocuments. Affected versions lack rate limiting on a Richdocuments OCS endpoint, potentially enabling enumeration of valid share tokens. CVSS 3.1 is 5.3: network-accessible, low complexity, no privileges, no user interaction, confidentiality impact only.
Likely exposure
Exposure is likely limited to Nextcloud deployments running the Richdocuments app versions below 3.8.4 or versions 4.0.0 through below 4.2.1, especially where the relevant OCS endpoint is reachable over the network.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The risk is plausible remote token enumeration, but the provided sources do not establish observed exploitation, exploit maturity, or confirmed compromise activity.
Researcher notes
Keep scope tied to Nextcloud Richdocuments, not Nextcloud core generally. The provided evidence identifies affected and fixed versions, CWE-200, and the rate-limit weakness, but does not include active exploitation evidence. Avoid inferring token compromise without log or incident evidence.
Mitigation direction
- Upgrade Nextcloud Richdocuments to 3.8.4, 4.2.1, or a later vendor-supported version.
- Disable the Richdocuments app if upgrading cannot be completed promptly.
- Review the Nextcloud advisory for deployment-specific guidance and version applicability.
- Monitor access logs for unusual repeated requests to Richdocuments OCS endpoints.
Validation and detection
- Inventory all Nextcloud deployments and record the installed Richdocuments app version.
- Confirm no deployment runs Richdocuments below 3.8.4 or 4.0.0 through below 4.2.1.
- Verify Richdocuments is disabled on systems awaiting the fixed version.
- Review logs for high-volume or patterned unauthenticated OCS endpoint requests.
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-200: 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 lookupCVE-2021-37629 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
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:N/S:U/C:L/I:N/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-gvvr-h36p-8mjxCVE reference · x_refsource_CONFIRM
- https://github.com/nextcloud/richdocuments/pull/1663CVE reference · x_refsource_MISC
- https://hackerone.com/reports/1258750CVE 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.
Exposure of Sensitive Information to an Unauthorized Actor
Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.