Security readout for executives and security teams
Plain-English summary
This CVE describes stored cross-site scripting in Zammad. A remote attacker could place web script or HTML through a User Avatar attribute, potentially causing code to run in another user's browser. The public bundle does not provide CVSS, detailed impact, a named fixed version, or evidence of active exploitation.
Executive priority
Treat this as a targeted remediation item for outdated Zammad deployments. Business urgency is higher for public helpdesk portals because successful XSS can affect user trust, sessions, and administrator-facing workflows.
Technical view
Zammad versions 1.0.x through 4.0.0 are described as affected by XSS via the User Avatar attribute. The vulnerability is client-side script execution in the web interface, not direct server code execution. Available sources do not include CWE, CVSS, exploit maturity, or remediation detail beyond the vendor advisory reference.
Likely exposure
Exposure is most likely in organizations still running Zammad 1.0.x through 4.0.0, especially customer-facing or internet-accessible helpdesk portals where avatar-related profile data may be influenced by remote users.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. The described attack path is remote injection of script or HTML through avatar metadata, with impact depending on where that data is rendered and which user views it.
Researcher notes
Evidence is limited to the CVE description and the Zammad advisory reference. Do not assume broader product impact, exploit availability, or a specific fixed release without consulting the vendor advisory.
Mitigation direction
- Identify whether any Zammad instance is version 1.0.x through 4.0.0.
- Review Zammad advisory ZAA-2021-06 for the vendor-supported fix or mitigation.
- Prioritize remediation for public-facing or customer-accessible Zammad portals.
- Monitor for suspicious avatar or profile changes until remediation is complete.
Validation and detection
- Confirm deployed Zammad versions from asset inventory or application administration records.
- Check whether affected instances expose user profile or avatar functionality to untrusted users.
- Review vendor advisory details before declaring the issue remediated.
- Verify remediation in staging before production rollout where operationally feasible.
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.
CVE-2021-35303 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://zammad.com/en/advisories/zaa-2021-06CVE reference · x_refsource_CONFIRM
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.