Security readout for executives and security teams
Plain-English summary
CVE-2021-4304 is a command injection flaw in eprintsug ulcc-core's CGI toolbox. A remote authenticated user could manipulate the password argument and cause system command execution. Public sources name a patch, but do not identify fixed releases or affected version ranges.
Executive priority
Treat this as a targeted remediation item. It is not KEV-confirmed exploited, but command injection in a web-accessible component can become serious where ulcc-core is exposed to users.
Technical view
The issue is CWE-77 in cgi/toolbox/toolbox, triggered through handling of the password argument. The CVSS v2 vector is AV:N/AC:L/Au:S/C:P/I:P/A:P, indicating network access, low complexity, single authentication, and partial confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to organizations running eprintsug ulcc-core with the affected CGI toolbox reachable to authenticated users. The source bundle lists versions as n/a, so asset owners must verify by code revision or vendor/project guidance.
Exploitation context
The sources state the attack can be launched remotely, but the CVSS vector indicates authentication is required. The CVE is not listed as KEV in the bundle, and no cited source confirms active exploitation.
Researcher notes
Evidence is sparse: affected versions are not enumerated, and the vulnerable functionality is described only as unknown functionality in cgi/toolbox/toolbox. Validate exposure through source revision and deployment review rather than relying on version strings.
Mitigation direction
- Apply the upstream patch commit 811edaae81eb044891594f00062a828f51b22cb1.
- Confirm deployed ulcc-core code includes the patched toolbox behavior.
- Check project or vendor guidance for fixed releases and supported upgrade paths.
- Review access to the CGI toolbox while remediation is pending.
Validation and detection
- Inventory systems running eprintsug ulcc-core.
- Determine whether cgi/toolbox/toolbox is deployed and reachable.
- Verify whether the patch commit is present in production code.
- Review authenticated access logs for unusual toolbox 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-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-4304 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 (2.0)
- Known Exploited
- No
- Published
Vector: AV:N/AC:L/Au:S/C:P/I:P/A:P
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.
AV:N/AC:L/Au:S/C:P/I:P/A:P86.4Primary CVE scoreVulnerability scoring details
Base CVSS 2.0 score
6.5MediumVector: AV:N/AC:L/Au:S/C:P/I:P/A:P
Source materials
- CVE List V5 sourceCVE List V5
- https://vuldb.com/?id.217447CVE reference · vdb-entry, technical-description
- https://vuldb.com/?ctiid.217447CVE reference · signature, permissions-required
- https://github.com/eprintsug/ulcc-core/commit/811edaae81eb044891594f00062a828f51b22cb1CVE reference · patch
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 Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.