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CVE Record

CVE-2021-26634: Maxboard multiple vulnerabilities

SQL injection and file upload attacks are possible due to insufficient validation of input values in some parameters and variables of files compromising Maxboard, which may lead to arbitrary code execution or privilege escalation. Attackers can use these vulnerabilities to perform attacks such as stealing server management rights using a web shell.

CriticalCVSS 9.8Not KEV-listedUpdated
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

Maxboard has critical flaws that could let an unauthenticated attacker attack the database or upload malicious files, potentially taking over the web server. The public record does not identify exact affected versions or a fixed release, so any Maxboard deployment should be treated as needing urgent verification.

Executive priority

Treat this as urgent if Maxboard exists in the environment. The score and impact justify rapid asset discovery and containment, but patch planning depends on vendor or KR CERT details not present here.

Technical view

The CVE describes SQL injection and unsafe file upload issues caused by insufficient input validation. Impact includes arbitrary code execution, privilege escalation, and possible web shell placement. CVSS 3.1 is 9.8 with network access, low complexity, no privileges, and no user interaction required. Version and patch details are not provided in the supplied sources.

Likely exposure

Exposure is most likely where Maxboard is deployed on internet-facing web servers. Because affected versions are unspecified, asset owners cannot scope risk by version from these sources alone.

Exploitation context

CISA KEV is false in the supplied bundle, and no cited source confirms active exploitation. The CVE description says attackers may steal server management rights using a web shell, but provides no exploit-status evidence.

Researcher notes

The public data is high-level: it names SQL injection, file upload, and CWE-288/CWE-434/CWE-89, but not vulnerable parameters, affected versions, exploit maturity, or fixed builds. Avoid assuming scope beyond Max Yi Maxboard.

Mitigation direction

  • Inventory all Maxboard deployments, including legacy or externally hosted instances.
  • Check Max Yi and KR CERT guidance for affected and fixed versions.
  • Remove public exposure until fixed-version status is confirmed.
  • Restrict upload functionality and administrative access where operationally possible.
  • Review web roots and upload paths for unauthorized executable files.

Validation and detection

  • Confirm whether any production, staging, or archived sites run Maxboard.
  • Identify the installed Maxboard version and compare it with vendor or KR CERT guidance.
  • Review web server logs for suspicious upload, database error, or admin-access patterns.
  • Check application directories for unexpected web shell-like files.
  • Verify internet-facing Maxboard instances are removed, restricted, or remediated.
Prepared
Confidence
medium
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

CWE-288: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookup
cwe · medium confidence lookup

CWE-434: File access and web shell behavior lookup

File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection 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 lookup
cwe · medium confidence lookup

CWE-89: Database access and collection lookup

Injection into data stores can inform collection, data access, and exfiltration detection reviews. 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 lookup
description · low confidence lookup

Execution 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 lookup
description · low confidence lookup

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
description · low confidence lookup

Database behavior lookup

The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
Vulnerability profileCVE Program record
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

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2021-26634Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Max YiMaxboardunspecifiedListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-288 · source CWE mapping

Authentication Bypass Using an Alternate Path or Channel

Authentication Bypass Using an Alternate Path or Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

CWE-434 · source CWE mapping

Unrestricted Upload of File with Dangerous Type

Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

CWE-89 · source CWE mapping

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.