Security readout for executives and security teams
Plain-English summary
CVE-2021-27961 is a reflected cross-site scripting issue in evesys versions 7.1 (2152) through 8.0 (2202). A crafted request to indexeva.php can cause attacker-supplied content to be reflected by the application. Business impact is most relevant where users access exposed evesys systems and trust browser-delivered content from them.
Executive priority
Handle as a moderate web application risk. It is not presented as actively exploited, but exposed affected systems can create phishing, session-trust, or user-content integrity risk. Remediate during the next security maintenance window, faster for internet-facing deployments.
Technical view
The CVE record describes CWE-79 reflected XSS through the indexeva.php action parameter. The listed CVSS 3.1 score is 6.5 with network access, low complexity, no privileges, and low confidentiality and integrity impact. The source bundle does not identify a fixed version, vendor advisory details, or confirmed exploitation.
Likely exposure
Exposure is limited to organizations running evesys 7.1 (2152) through 8.0 (2202), especially if the application is reachable by users over a network. The supplied affected-product metadata is incomplete, so confirm product naming and versions from local inventory and vendor records.
Exploitation context
The CVE is not listed as KEV in the supplied bundle. The references include a public gist, but the bundle does not prove active exploitation. Treat it as publicly documented and potentially testable, not as confirmed exploited in the wild.
Researcher notes
Evidence is sparse. The CVE description identifies the vulnerable parameter and version range, but affected CPEs, patch status, and vendor remediation details are not provided in the bundle. Avoid assuming product variants or exploit maturity beyond the cited records.
Mitigation direction
- Check evesys/evasys vendor guidance for fixed versions or official mitigations.
- Prioritize upgrade or remediation for externally reachable affected systems.
- Restrict access to affected instances where business operations allow.
- Ensure application output encoding is enforced for reflected request parameters.
- Increase monitoring for unusual requests targeting indexeva.php.
Validation and detection
- Inventory evesys deployments and confirm exact versions against 7.1 (2152) through 8.0 (2202).
- Identify whether indexeva.php is reachable from untrusted networks.
- Review application logs for suspicious action-parameter activity.
- Use authorized internal testing to confirm reflected input is safely encoded.
- Document whether vendor guidance or a fixed release has been applied.
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-2021-27961 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
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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:N/UI:N/S:U/C:L/I:L/A:N3.92.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://evasys.de/en/blog/CVE reference
- https://gist.github.com/phlmox/c24bf28f12fbc0f2ea73dd9e8cfa94e3CVE 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.