Security readout for executives and security teams
Plain-English summary
Cachet status page installations before 2.5.1 let any logged-in user, even a low-privilege user, make the application run its installer again. The sources say this can lead to arbitrary code execution on the server. Organizations running Cachet should treat this as high urgency if the administration dashboard is reachable.
Executive priority
Prioritize remediation quickly for any production Cachet instance, especially public-facing status infrastructure. The impact is server code execution after authenticated access, so this can move from a minor account compromise to full system compromise.
Technical view
CVE-2021-39173 affects fiveai Cachet versions before 2.5.1. The issue is described as forced reinstall due to insufficient validation in the ReadyForUse middleware, tied to instance name handling. It requires authenticated access, has low attack complexity, and can affect confidentiality, integrity, and availability.
Likely exposure
Exposure is most likely in self-hosted Cachet deployments below 2.5.1 where an attacker can authenticate to the dashboard. Internet-reachable administration dashboards increase practical risk, especially where untrusted or weakly controlled user accounts exist.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Public sources describe the vulnerability and its impact, but active exploitation should not be assumed from the provided evidence.
Researcher notes
The fix is described as stricter ReadyForUse middleware validation of the instance name. CWE-704 is listed. Keep validation non-invasive: confirm version, dashboard exposure, user access model, and configuration integrity rather than attempting reinstall behavior.
Mitigation direction
- Upgrade Cachet to version 2.5.1 or later.
- Restrict administration dashboard access to trusted source IP addresses.
- Review and remove unnecessary Cachet user accounts.
- Check vendor advisory and release notes before operational changes.
- Prioritize exposed administration dashboards first.
Validation and detection
- Inventory all Cachet instances and record their versions.
- Confirm affected systems are upgraded to 2.5.1 or later.
- Verify dashboard access is limited to trusted networks or IPs.
- Review Cachet users for unexpected or unnecessary accounts.
- Check logs for unusual setup, install, or configuration activity.
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-704: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-39173 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/fiveai/Cachet/releases/tag/v2.5.1CVE reference · x_refsource_MISC
- https://github.com/fiveai/Cachet/security/advisories/GHSA-r67m-m8c7-jp83CVE reference · x_refsource_CONFIRM
- https://blog.sonarsource.com/cachet-code-execution-via-laravel-configuration-injection/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.
Incorrect Type Conversion or Cast
Incorrect Type Conversion or Cast represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.