Security readout for executives and security teams
Plain-English summary
CVE-2021-35300 is a content spoofing issue in Zammad's 404 page. A remote attacker could manipulate displayed text to steer users toward an attacker-controlled page. The source bundle does not indicate code execution, data theft, CVSS scoring, or confirmed exploitation.
Executive priority
Treat this as a moderate-priority brand trust and phishing-enablement issue. It does not appear to be a direct server takeover from the provided evidence, but public support portals can amplify social engineering risk.
Technical view
Zammad 1.0.x through 4.0.0 are reported affected by text injection/content spoofing in the 404 page. The weakness is user-facing trust manipulation rather than a confirmed server compromise path. Public source details are limited to the CVE description and Zammad advisory reference.
Likely exposure
Exposure is most likely on public-facing Zammad support portals running versions 1.0.x through 4.0.0, where unauthenticated users can reach 404 pages and may trust the portal branding.
Exploitation context
The sources describe a remote attacker manipulating users into visiting an attacker page. CISA KEV is false in the bundle, and no cited source confirms active exploitation or published exploit tooling.
Researcher notes
Evidence is sparse: no CVSS vector, CWE, exploit status, or detailed patch information appears in the supplied bundle. Validate affected versions against Zammad advisory ZAA-2021-07 before making remediation claims.
Mitigation direction
- Inventory Zammad deployments and record running versions.
- Prioritize any Zammad 1.0.x through 4.0.0 instances.
- Review Zammad advisory ZAA-2021-07 for vendor-approved remediation.
- Upgrade or apply vendor guidance where affected versions are found.
- Warn support teams about spoofed links using trusted portal branding.
Validation and detection
- Confirm Zammad version from administrative or asset inventory records.
- Check whether the customer portal is internet-facing.
- Review 404 page behavior in a safe test environment.
- Search web logs for unusual 404 traffic patterns.
- Confirm remediation against Zammad advisory guidance.
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-2021-35300 mapping review
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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-2021-07CVE 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.