Skip to content

CVE-2026-96656 · CVE record: PUBLISHED

Plex Media Server arbitrary file write

Plex Media Server

Plex Media Server before 1.43.3.10861 allows an admin user to write arbitrary files that may be executed on load. The preference TranscoderH264Options is appended verbatim to x264's option string on every transcode. At startup, all .so files are run without signature, execute bit, or symbol checks.

Exploitation evidence

Known exploited · CISA KEV listed

Added 2026-10-20. Ransomware campaign use: Unknown.

CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA due date: 2026-10-23. 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

Plex / Media Server

Default status: unknown

affected: 0 to < 1.43.3.10861 (custom)
unaffected: 1.43.3.10861

Fixes and workarounds

No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.

Sources and related reporting

CVE Program record ↗ · Download tracked evidence as JSON

Monitored source mentions

Shared CVE identifiers link source mentions; they do not establish that the reports describe the same incident.

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": 0.01785,
  "percentile": 0.78621
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.01785,
  "percentile": 0.78487
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.01785,
  "percentile": 0.7846
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.01785,
  "percentile": 0.78451
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.01785,
  "percentile": 0.78435
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.01785,
  "percentile": 0.784
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.01785,
  "percentile": 0.78384
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.01785,
  "percentile": 0.78368
}

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

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.01785,
  "percentile": 0.78328
}

03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.01785,
  "percentile": 0.78303
}

03 Nov 2026, 02:22 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-96656",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-19T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2026-10-20",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-96656"
              },
              "type": "kev"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-21T03:56:10.489Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "third-party-advisory"
            ],
            "url": "https://www.boredhackerblog.info/2026/10/plex-vulnerabilities-being-exploited-in.html"
          },
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-96656"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2026-10-20T00:00:00.000Z",
            "value": "CVE-2026-96656 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Media Server",
          "vendor": "Plex",
          "versions": [
            {
              "lessThan": "1.43.3.10861",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            },
            {
              "status": "unaffected",
              "version": "1.43.3.10861"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Zach Main"
        }
      ],
      "datePublic": "2026-08-03T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Plex Media Server before 1.43.3.10861 allows an admin user to write arbitrary files that may be executed on load. The preference TranscoderH264Options is appended verbatim to x264's option string on every transcode. At startup, all .so files are run without signature, execute bit, or symbol checks."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "privilegesRequired": "HIGH",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        },
        {
          "other": {
            "content": {
              "id": "CVE-2026-96656",
              "options": [
                {
                  "Exploitation": "none"
                },
                {
                  "Automatable": "no"
                },
                {
                  "Technical Impact": "total"
                }
              ],
              "role": "CISA Coordinator",
              "timestamp": "2026-09-14T18:24:56.053053Z",
              "version": "2.0.3"
            },
            "type": "ssvc"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-73",
              "description": "CWE-73 External Control of File Name or Path",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-23T16:07:10.048Z",
        "orgId": "9119a7d8-5eab-497f-8521-727c672e3725",
        "shortName": "cisa-cg"
      },
      "references": [
        {
          "name": "url",
          "tags": [
            "release-notes"
          ],
          "url": "https://forums.plex.tv/t/plex-media-server/30447/711"
        },
        {
          "name": "url",
          "tags": [
            "vdb-entry"
          ],
          "url": "https://www.cve.org/CVERecord?id=CVE-2026-96656"
        },
        {
          "name": "url",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-266-01.json"
        },
        {
          "name": "url",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://zmain.info/blog/plex2shell"
        }
      ],
      "title": "Plex Media Server arbitrary file write"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9119a7d8-5eab-497f-8521-727c672e3725",
    "assignerShortName": "cisa-cg",
    "cveId": "CVE-2026-96656",
    "datePublished": "2026-09-23T16:07:10.048Z",
    "dateReserved": "2026-09-23T14:42:33.270Z",
    "dateUpdated": "2026-10-21T03:56:10.489Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2026-96656",
  "cwes": [
    "CWE-73"
  ],
  "dateAdded": "2026-10-20",
  "dueDate": "2026-10-23",
  "forensicTriage": "Yes",
  "knownRansomwareCampaignUse": "Unknown",
  "notes": "https://forums.plex.tv/t/important-security-update-for-plex-media-server-v1-43-2-and-earlier/942319 ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-96656",
  "product": "Media Server",
  "requiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
  "shortDescription": "Plex Media Server contains an external control of file name or path vulnerability which can allow an admin user to write arbitrary files that may be executed on load. This vulnerability can be chained with CVE-2026-96652, CVE-2026-96654, and CVE-2026-96655.",
  "vendorProject": "Plex",
  "vulnerabilityName": "Plex Media Server External Control of File Name or Path Vulnerability"
}

Egret — Back to top Egret