FKIE_CVE-2026-45257

Vulnerability from fkie_nvd - Published: 2026-06-26 15:16 - Updated: 2026-06-27 05:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
The KTLS receive path decrypted each record in place, assuming that the mbufs holding received data were anonymous and safe to modify. This assumption does not hold for data placed on a socket by sendfile(2), which can reference file-backed memory directly through non-anonymous M_EXTPG pages or EXT_SFBUF mbufs. When the sender transmits such data over a loopback connection without enabling KTLS on the transmit side, the file-backed mbufs reach the receiver's decryption path unchanged. Decrypting a record in place then overwrites the backing file's page cache instead of a private copy of the data. An unprivileged local user who can read a file can overwrite its contents with data of their choosing by sending the file over a loopback connection on which they have enabled KTLS receive. The write modifies the page cache directly, so it bypasses file flags such as schg and is written back to disk. By overwriting a setuid binary or other trusted file, a local user can escalate privileges, potentially gaining full control of the affected system.
References
secteam@freebsd.orghttps://security.freebsd.org/advisories/FreeBSD-SA-26:26.ktls.ascVendor Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2026/06/10/20Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2026/06/10/21Mailing List, Third Party Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.heise.de/en/news/FreeBSD-Privilege-Escalation-Vulnerability-with-Tongue-in-Cheek-Codename-11329109.htmlThird Party Advisory
Impacted products
Vendor Product Version
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.1
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "ktls"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
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              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            },
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              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
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              "lessThan": "p15",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            }
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        }
      ],
      "source": "secteam@freebsd.org"
    }
  ],
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The KTLS receive path decrypted each record in place, assuming that the mbufs holding received data were anonymous and safe to modify.  This assumption does not hold for data placed on a socket by sendfile(2), which can reference file-backed memory directly through non-anonymous M_EXTPG pages or EXT_SFBUF mbufs.  When the sender transmits such data over a loopback connection without enabling KTLS on the transmit side, the file-backed mbufs reach the receiver\u0027s decryption path unchanged.  Decrypting a record in place then overwrites the backing file\u0027s page cache instead of a private copy of the data.\n\nAn unprivileged local user who can read a file can overwrite its contents with data of their choosing by sending the file over a loopback connection on which they have enabled KTLS receive.  The write modifies the page cache directly, so it bypasses file flags such as schg and is written back to disk.  By overwriting a setuid binary or other trusted file, a local user can escalate privileges, potentially gaining full control of the affected system."
    }
  ],
  "id": "CVE-2026-45257",
  "lastModified": "2026-06-27T05:16:45.920",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-45257",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-11T00:00:00+00:00",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-26T15:16:39.280",
  "references": [
    {
      "source": "secteam@freebsd.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:26.ktls.asc"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://www.openwall.com/lists/oss-security/2026/06/10/20"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://www.openwall.com/lists/oss-security/2026/06/10/21"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://www.heise.de/en/news/FreeBSD-Privilege-Escalation-Vulnerability-with-Tongue-in-Cheek-Codename-11329109.html"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-123"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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