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CVE-2025-3935 · CVE record: PUBLISHED

ScreenConnect Exposure to ASP.NET ViewState Code Injection

ConnectWise ScreenConnect

ScreenConnect versions 25.2.3 and earlier versions may be susceptible to a ViewState code injection attack. ASP.NET Web Forms use ViewState to preserve page and control state, with data encoded using Base64 protected by machine keys. It is important to note that to obtain these machine keys, privileged system level access must be obtained. If these machine keys are compromised, attackers could create and send a malicious ViewState to the website, potentially leading to remote code execution on the server. The risk does not originate from a vulnerability introduced by ScreenConnect, but from platform level behavior. This had no direct impact to ScreenConnect Client. ScreenConnect 2025.4 patch disables ViewState and removes any dependency on it.

Exploitation evidence

Known exploited · CISA KEV listed

Added 2025-06-02. Ransomware campaign use: Unknown.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA due date: 2025-06-23. This is the catalog’s deadline, not an assessment of your organization’s exposure.

KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗

Reported products and versions

ConnectWise / ScreenConnect

Default status: unaffected

affected: <25.2.3

Fixes and workarounds

Cloud: No action is required. On-premises: Upgrade to the latest stable version. Details and guidance can be found here: ScreenConnect 25.2.4 Security Patch https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4

Sources and related reporting

CVE Program record ↗ · Download tracked evidence as JSON

Observed change timeline

History begins when Egret first downloads each source. It is not the complete upstream CVE history.

12 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-12",
  "epss": 0.03597,
  "percentile": 0.89613
}

10 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.03597,
  "percentile": 0.89547
}

09 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.03597,
  "percentile": 0.89535
}

08 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.03597,
  "percentile": 0.8953
}

07 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.03597,
  "percentile": 0.89522
}

06 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.03597,
  "percentile": 0.89505
}

06 Nov 2026, 06:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.03597,
  "percentile": 0.89495
}

04 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.03597,
  "percentile": 0.89487
}

03 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.03597,
  "percentile": 0.89468
}

03 Nov 2026, 18:20 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-3935",
                "options": [
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                    "Exploitation": "active"
                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-06-06T03:55:32.340641Z",
                "version": "2.0.3"
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          {
            "other": {
              "content": {
                "dateAdded": "2025-06-02",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3935"
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        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-26T18:28:01.567Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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        "references": [
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            "tags": [
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            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3935"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2025-06-02T00:00:00.000Z",
            "value": "CVE-2025-3935 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "Microsoft ASP.NET"
          ],
          "product": "ScreenConnect",
          "vendor": "ConnectWise",
          "versions": [
            {
              "status": "affected",
              "version": "<25.2.3"
            }
          ]
        }
      ],
      "descriptions": [
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              "value": "<span style=\"background-color: rgb(255, 255, 255);\">ScreenConnect versions 25.2.3 and earlier versions may be susceptible to a ViewState code injection attack. ASP.NET Web Forms use ViewState to preserve page and control state, with data encoded using Base64 protected by machine keys.&nbsp;\n<span style=\"background-color: rgb(255, 255, 255);\">It is important to note that to obtain these machine keys, privileged system level access must be obtained. </span>\n\n</span><br><br>I<span style=\"background-color: rgb(255, 255, 255);\">f these machine keys are compromised, attackers could create and send a malicious ViewState to the website, potentially leading to remote code execution on the server.&nbsp;</span><span style=\"background-color: rgb(255, 255, 255);\"><br></span>\n\n<br>The risk does not originate from a vulnerability introduced by ScreenConnect, but from platform level behavior.&nbsp; This had no direct impact to ScreenConnect Client.&nbsp;<span style=\"background-color: rgb(255, 255, 255);\">ScreenConnect 2025.4 patch disables ViewState and removes any dependency on it. </span><span style=\"background-color: rgb(255, 255, 255);\">&nbsp;</span>"
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          ],
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      "impacts": [
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          "capecId": "CAPEC-115",
          "descriptions": [
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              "lang": "en",
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      "metrics": [
        {
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            "attackComplexity": "HIGH",
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            "baseScore": 8.1,
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            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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      "problemTypes": [
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          "descriptions": [
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      "providerMetadata": {
        "dateUpdated": "2025-09-03T16:31:13.339Z",
        "orgId": "7d616e1a-3288-43b1-a0dd-0a65d3e70a49",
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      "references": [
        {
          "url": "https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4"
        },
        {
          "url": "https://www.connectwise.com/company/trust/advisories"
        }
      ],
      "solutions": [
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              "base64": false,
              "type": "text/html",
              "value": "<p></p><b>Cloud:&nbsp;</b>No action is required. <br><br><b>On-premises:&nbsp;</b>Upgrade to the latest stable version.<br>\n\n\n\n\n\n\n\n\n\n<p>Details and guidance can be found here:\n\n<a target=\"_blank\" rel=\"nofollow\" href=\"https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4\">ScreenConnect 25.2.4 Security Patch</a>\n\n</p>\n\n\n\n\n<br>"
            }
          ],
          "value": "Cloud: No action is required. \n\nOn-premises: Upgrade to the latest stable version.\n\n\n\n\n\n\n\n\n\n\nDetails and guidance can be found here:\n\n ScreenConnect 25.2.4 Security Patch https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "ScreenConnect Exposure to ASP.NET ViewState Code Injection",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "7d616e1a-3288-43b1-a0dd-0a65d3e70a49",
    "assignerShortName": "ConnectWise",
    "cveId": "CVE-2025-3935",
    "datePublished": "2025-04-25T18:27:44.244Z",
    "dateReserved": "2025-04-25T14:32:25.365Z",
    "dateUpdated": "2026-02-26T18:28:01.567Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
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03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.03597,
  "percentile": 0.89455
}

03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2025-3935",
  "cwes": [
    "CWE-287"
  ],
  "dateAdded": "2025-06-02",
  "dueDate": "2025-06-23",
  "forensicTriage": "No",
  "knownRansomwareCampaignUse": "Unknown",
  "notes": "https://www.connectwise.com/company/trust/security-bulletins/screenconnect-security-patch-2025.4 ;   https://nvd.nist.gov/vuln/detail/CVE-2025-3935",
  "product": "ScreenConnect",
  "requiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
  "shortDescription": "ConnectWise ScreenConnect contains an improper authentication vulnerability. This vulnerability could allow a ViewState code injection attack, which could allow remote code execution if machine keys are compromised.",
  "vendorProject": "ConnectWise",
  "vulnerabilityName": "ConnectWise ScreenConnect Improper Authentication Vulnerability"
}

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