Security readout for executives and security teams
Plain-English summary
OpenCATS 0.9.6 allowed a logged-in restricted user to place JavaScript in a calendar event description. If another user viewed that event, the script could run in their browser. The stated impact includes session token theft or unintended user actions, but it requires attacker login and victim interaction.
Executive priority
Treat as a moderate-priority application security issue. It is not cited as actively exploited, but it can affect higher-privilege users if untrusted authenticated accounts can plant content they later view.
Technical view
This is a stored cross-site scripting issue, CWE-79, in OpenCATS 0.9.6 calendar event descriptions. CVSS 3.1 is 5.4: network reachable, low complexity, low privileges required, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.
Likely exposure
Exposure is limited to OpenCATS 0.9.6 deployments where restricted authenticated accounts can create or edit calendar event descriptions and higher-privilege users may view those events.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The attack scenario is authenticated stored XSS requiring a victim to browse to the malicious calendar event.
Researcher notes
Evidence supports stored XSS only for OpenCATS 0.9.6. The bundle does not identify a fixed version, patch commit, or real-world exploitation. Avoid assuming broader version impact without vendor or advisory confirmation.
Mitigation direction
- Identify and prioritize any OpenCATS 0.9.6 deployments.
- Check OpenCATS or Tenable guidance for an official fixed version or patch.
- Restrict calendar event creation or editing to trusted users until remediated.
- Review output encoding and input neutralization for calendar event descriptions.
- Audit suspicious calendar descriptions and privileged account activity.
Validation and detection
- Confirm whether deployed OpenCATS version is 0.9.6.
- Verify restricted accounts can create or modify calendar event descriptions.
- Check whether event descriptions are safely encoded when viewed by other users.
- Review logs for unusual calendar edits or privileged-user actions after event views.
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-2023-27294 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
- 5.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/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:L/UI:R/S:C/C:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.tenable.com/security/research/tra-2023-8CVE 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.