GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

FKIE_CVE-2026-55194

Vulnerability from fkie_nvd - Published: 2026-08-19 18:16 - Updated: 2026-09-09 21:19
Severity
8.7 (High) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Summary
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0.
References
security-advisories@github.comhttps://github.com/FreeRDP/FreeRDP/commit/9f2da52c2341cc14a96ad12e69c5b83d0bcd8b5a
security-advisories@github.comhttps://github.com/FreeRDP/FreeRDP/pull/12873
security-advisories@github.comhttps://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0
security-advisories@github.comhttps://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9gxm-3mf5-f5cx
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "FreeRDP",
          "vendor": "FreeRDP",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.27.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu-\u003es buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0."
    }
  ],
  "id": "CVE-2026-55194",
  "lastModified": "2026-09-09T21:19:49.197",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55194",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-21T03:55:49.884406Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-19T18:16:44.857",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/FreeRDP/FreeRDP/commit/9f2da52c2341cc14a96ad12e69c5b83d0bcd8b5a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/FreeRDP/FreeRDP/pull/12873"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9gxm-3mf5-f5cx"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.