Vulnerability-Lookup

GHSA-F965-GHFW-X6JX

Vulnerability from github – Published: 2026-05-01 00:31 – Updated: 2026-05-01 03:31

Details

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

Severity ?

3.7 (Low)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-40686"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-30T22:16:25Z",
    "severity": "LOW"
  },
  "details": "In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.",
  "id": "GHSA-f965-ghfw-x6jx",
  "modified": "2026-05-01T03:31:23Z",
  "published": "2026-05-01T00:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40686"
    },
    {
      "type": "WEB",
      "url": "https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc"
    },
    {
      "type": "WEB",
      "url": "https://exim.org/static/doc/security/CVE-2025-40686.txt"
    },
    {
      "type": "WEB",
      "url": "https://exim.org/static/doc/security/CVE-2026-40686.txt"
    },
    {
      "type": "WEB",
      "url": "https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment"
    },
    {
      "type": "WEB",
      "url": "https://www.openwall.com/lists/oss-security/2026/04/30/21"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-40686 (GCVE-0-2026-40686)

Vulnerability from cvelistv5 – Published: 2026-04-30 00:00 – Updated: 2026-05-01 14:27

Summary

Severity ?

3.7 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CWE

CWE-125 - Out-of-bounds Read

Assigner

mitre

References

4 references

URL	Tags
https://www.openwall.com/lists/oss-security/2026/…
https://exim.org/static/doc/security/cve-2026-04.…
https://code.exim.org/exim/exim/commit/f2570bde16…
https://exim.org/static/doc/security/CVE-2026-40686.txt

Impacted products

1 product

Vendor	Product	Version
Exim	Exim	Affected: 0 , < 4.99.2 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-40686",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-01T14:27:01.351716Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-01T14:27:11.390Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Exim",
          "vendor": "Exim",
          "versions": [
            {
              "lessThan": "4.99.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.99.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.7,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-125",
              "description": "CWE-125 Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-01T01:19:46.987Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://www.openwall.com/lists/oss-security/2026/04/30/21"
        },
        {
          "url": "https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment"
        },
        {
          "url": "https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc"
        },
        {
          "url": "https://exim.org/static/doc/security/CVE-2026-40686.txt"
        }
      ],
      "x_generator": {
        "engine": "enrichogram 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-40686",
    "datePublished": "2026-04-30T00:00:00.000Z",
    "dateReserved": "2026-04-14T00:00:00.000Z",
    "dateUpdated": "2026-05-01T14:27:11.390Z",
    "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.

Action not permitted

GHSA-F965-GHFW-X6JX

CVE-2026-40686 (GCVE-0-2026-40686)

Tags

Sightings

Nomenclature