Security readout for executives and security teams
Plain-English summary
SeaCMS 11.4 has a critical flaw that can let a remote attacker run PHP code on the server. In business terms, a vulnerable public deployment could become fully compromised, exposing data and allowing site takeover. The official affected-product metadata is incomplete, so exposure should be confirmed by inventory.
Executive priority
Treat this as urgent for any internet-facing SeaCMS 11.4 site. The impact is potential server takeover, but urgency depends on whether the product is actually deployed and reachable. No active exploitation evidence was provided, so prioritize rapid inventory, exposure reduction, and vendor-guided remediation.
Technical view
The CVE describes arbitrary PHP code execution in SeaCMS 11.4 through /Upload/admin/admin_notify.php involving the notify1 parameter when action is set. It is classified as CWE-94 with CVSS 3.1 score 9.8: network reachable, low complexity, no privileges, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Likely exposure is limited to organizations running SeaCMS 11.4, especially if the affected admin upload path is reachable over the network. The CVE record’s affected vendor/product fields are listed as n/a, so teams should verify deployments by software inventory and application fingerprinting rather than relying only on CPE matching.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. The CVSS vector indicates the issue is remotely reachable and unauthenticated, which makes internet-facing deployments high risk. The GitHub issue is the only public technical reference in the supplied bundle.
Researcher notes
Evidence is sparse but serious: CVE text identifies the vulnerable file, parameter condition, SeaCMS 11.4, CWE-94, and CVSS 9.8. Affected CPE/product metadata is absent, and no patch version is named in the supplied sources. Avoid assuming broader SeaCMS versions are affected without vendor confirmation.
Mitigation direction
- Identify any SeaCMS 11.4 deployments and prioritize them for review.
- Check SeaCMS vendor or project guidance for a fixed version or official workaround.
- Restrict public network access to /Upload/admin/ paths until remediation is confirmed.
- Remove or isolate unsupported SeaCMS instances if no maintained fix is available.
- Monitor web logs for requests targeting admin_notify.php.
Validation and detection
- Confirm whether SeaCMS 11.4 is present in application inventory.
- Verify the affected admin path is not publicly reachable.
- Review web server logs for suspicious admin_notify.php requests.
- Confirm remediation against vendor guidance before closing the finding.
- Document any compensating controls if no patch is available.
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-94: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process 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 lookupCVE-2021-39426 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/seacms-com/seacms/issues/21CVE 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 Control of Generation of Code ('Code Injection')
Improper Control of Generation of Code ('Code Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.