FKIE_CVE-2026-4115

Vulnerability from fkie_nvd - Published: 2026-03-22 13:16 - Updated: 2026-03-23 14:31
Severity ?
3.7 (Low) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Summary
A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may be used. The real existence of this vulnerability is still doubted at the moment. The patch is identified as af996b5ec27ab79bae3882071b9d6acf16044549. It is advisable to implement a patch to correct this issue. The vendor was contacted early, responded in a very professional manner and quickly released a patch for the affected product. However, at the moment there is no proof that this flaw might have any real-world impact.
References
cna@vuldb.comhttps://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=af996b5ec27ab79bae3882071b9d6acf16044549
cna@vuldb.comhttps://github.com/py-thok/putty-ed25519-malleability-s-plus-l
cna@vuldb.comhttps://github.com/py-thok/putty-ed25519-malleability-s-plus-l/blob/main/poc.py
cna@vuldb.comhttps://vuldb.com/?ctiid.352429
cna@vuldb.comhttps://vuldb.com/?id.352429
cna@vuldb.comhttps://vuldb.com/?submit.775576
cna@vuldb.comhttps://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/eddsa-overlarge-s.html
cna@vuldb.comhttps://www.rfc-editor.org/rfc/rfc8032#section-8.4
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [
    {
      "sourceIdentifier": "cna@vuldb.com",
      "tags": [
        "disputed"
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may be used. The real existence of this vulnerability is still doubted at the moment. The patch is identified as af996b5ec27ab79bae3882071b9d6acf16044549. It is advisable to implement a patch to correct this issue. The vendor was contacted early, responded in a very professional manner and quickly released a patch for the affected product. However, at the moment there is no proof that this flaw might have any real-world impact."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad fue detectada en PuTTY 0.83. Afectada es la funci\u00f3n eddsa_verify del archivo crypto/ecc-ssh.c del componente Gestor de Firma Ed25519. La manipulaci\u00f3n resulta en verificaci\u00f3n impropia de firma criptogr\u00e1fica. El ataque puede ser realizado desde remoto. El ataque requiere un alto nivel de complejidad. La explotabilidad se dice que es dif\u00edcil. El exploit es ahora p\u00fablico y puede ser usado. La existencia real de esta vulnerabilidad todav\u00eda se duda en este momento. El parche se identifica como af996b5ec27ab79bae3882071b9d6acf16044549. Es aconsejable implementar un parche para corregir este problema. El proveedor fue contactado temprano, respondi\u00f3 de manera muy profesional y r\u00e1pidamente lanz\u00f3 un parche para el producto afectado. Sin embargo, en este momento no hay prueba de que este fallo pueda tener alg\u00fan impacto en el mundo real."
    }
  ],
  "id": "CVE-2026-4115",
  "lastModified": "2026-03-23T14:31:37.267",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "HIGH",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 2.6,
          "confidentialityImpact": "NONE",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:H/Au:N/C:N/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 4.9,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "cna@vuldb.com",
        "type": "Secondary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 1.4,
        "source": "cna@vuldb.com",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "HIGH",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "PROOF_OF_CONCEPT",
          "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": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/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": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cna@vuldb.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-22T13:16:20.377",
  "references": [
    {
      "source": "cna@vuldb.com",
      "url": "https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=af996b5ec27ab79bae3882071b9d6acf16044549"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://github.com/py-thok/putty-ed25519-malleability-s-plus-l"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://github.com/py-thok/putty-ed25519-malleability-s-plus-l/blob/main/poc.py"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://vuldb.com/?ctiid.352429"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://vuldb.com/?id.352429"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://vuldb.com/?submit.775576"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/eddsa-overlarge-s.html"
    },
    {
      "source": "cna@vuldb.com",
      "url": "https://www.rfc-editor.org/rfc/rfc8032#section-8.4"
    }
  ],
  "sourceIdentifier": "cna@vuldb.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        },
        {
          "lang": "en",
          "value": "CWE-347"
        }
      ],
      "source": "cna@vuldb.com",
      "type": "Primary"
    }
  ]
}


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  • 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.
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