Vulnerability-Lookup

FKIE_CVE-2026-58317

Vulnerability from fkie_nvd - Published: 2026-07-17 05:16 - Updated: 2026-07-17 17:56

Severity

6.3 (Medium) - CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

Summary

Unsigned to Signed Conversion Error (CWE-196) vulnerability exists in TTSSH2 plugin of Tera Term provided by TeraTerm Project. When Tera Term attempts to establish an SSH connection to a server set up by an attacker, out-of-bounds read/write may occur. As a result, the contents of adjacent memory regions may be transmitted to the server, and Tera Term may behave unexpected or terminate abnormally.

References

	URL	Tags
	vultures@jpcert.or.jp	https://jvn.jp/en/jp/JVN65294474/
	vultures@jpcert.or.jp	https://teratermproject.github.io/SA/JVN65294474-en.html
	vultures@jpcert.or.jp	https://teratermproject.github.io/SA/JVN65294474.html

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "TTSSH2",
          "vendor": "TeraTerm Project",
          "versions": [
            {
              "lessThanOrEqual": "3.6.1",
              "status": "affected",
              "version": "1.00 alpha1",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vultures@jpcert.or.jp"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Unsigned to Signed Conversion Error (CWE-196) vulnerability exists in TTSSH2 plugin of Tera Term provided by TeraTerm Project. When Tera Term attempts to establish an SSH connection to a server set up by an attacker, out-of-bounds read/write may occur. As a result, the contents of adjacent memory regions may be transmitted to the server, and Tera Term may behave unexpected or terminate abnormally."
    }
  ],
  "id": "CVE-2026-58317",
  "lastModified": "2026-07-17T17:56:08.130",
  "metrics": {
    "cvssMetricV30": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L",
          "version": "3.0"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.4,
        "source": "vultures@jpcert.or.jp",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.1,
          "baseSeverity": "MEDIUM",
          "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": "ACTIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/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": "LOW",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "vultures@jpcert.or.jp",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-58317",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-17T13:06:11.360435Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-17T05:16:40.180",
  "references": [
    {
      "source": "vultures@jpcert.or.jp",
      "url": "https://jvn.jp/en/jp/JVN65294474/"
    },
    {
      "source": "vultures@jpcert.or.jp",
      "url": "https://teratermproject.github.io/SA/JVN65294474-en.html"
    },
    {
      "source": "vultures@jpcert.or.jp",
      "url": "https://teratermproject.github.io/SA/JVN65294474.html"
    }
  ],
  "sourceIdentifier": "vultures@jpcert.or.jp",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-196"
        }
      ],
      "source": "vultures@jpcert.or.jp",
      "type": "Secondary"
    }
  ]
}

CVE-2026-58317 (GCVE-0-2026-58317)

Vulnerability from cvelistv5 – Published: 2026-07-17 04:14 – Updated: 2026-07-17 13:06

Summary

Severity

6.3 (Medium)


                        
                          CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

5.1 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-17 13:06 UTC

CWE

CWE-196 - Unsigned to signed conversion error

Assigner

jpcert jpcert root

References

3 references

URL	Tags
https://teratermproject.github.io/SA/JVN65294474-…
https://teratermproject.github.io/SA/JVN65294474.html
https://jvn.jp/en/jp/JVN65294474/

Impacted products

1 product

Vendor	Product	Version
TeraTerm Project	TTSSH2	Affected: 1.00 alpha1 , ≤ 3.6.1 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-58317",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-17T13:06:11.360435Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-17T13:06:39.880Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "TTSSH2",
          "vendor": "TeraTerm Project",
          "versions": [
            {
              "lessThanOrEqual": "3.6.1",
              "status": "affected",
              "version": "1.00 alpha1",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Unsigned to Signed Conversion Error (CWE-196) vulnerability exists in TTSSH2 plugin of Tera Term provided by TeraTerm Project. When Tera Term attempts to establish an SSH connection to a server set up by an attacker, out-of-bounds read/write may occur. As a result, the contents of adjacent memory regions may be transmitted to the server, and Tera Term may behave unexpected or terminate abnormally."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L",
            "version": "3.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "baseScore": 5.1,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-196",
              "description": "Unsigned to signed conversion error",
              "lang": "en-US",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-17T04:14:03.592Z",
        "orgId": "ede6fdc4-6654-4307-a26d-3331c018e2ce",
        "shortName": "jpcert"
      },
      "references": [
        {
          "url": "https://teratermproject.github.io/SA/JVN65294474-en.html"
        },
        {
          "url": "https://teratermproject.github.io/SA/JVN65294474.html"
        },
        {
          "url": "https://jvn.jp/en/jp/JVN65294474/"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ede6fdc4-6654-4307-a26d-3331c018e2ce",
    "assignerShortName": "jpcert",
    "cveId": "CVE-2026-58317",
    "datePublished": "2026-07-17T04:14:03.592Z",
    "dateReserved": "2026-07-10T02:15:08.138Z",
    "dateUpdated": "2026-07-17T13:06:39.880Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.