CVE-2026-15779 (GCVE-0-2026-15779)

Vulnerability from cvelistv5 – Published: 2026-07-15 12:33 – Updated: 2026-07-15 13:04
VLAI
Title
Samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation
Summary
A flaw was found in samba's pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account's home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.
Severity
6.1 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-732 - Incorrect Permission Assignment for Critical Resource
Assigner
References
Impacted products
Date Public
2026-07-14 00:00
Credits
This issue was discovered by Runar Lundgren (Red Hat).
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-15779",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-15T13:04:26.614098Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-15T13:04:49.311Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "samba-winbind",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
          ],
          "defaultStatus": "unknown",
          "packageName": "samba-winbind",
          "product": "Red Hat Enterprise Linux 6",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "defaultStatus": "affected",
          "packageName": "samba-winbind",
          "product": "Red Hat Enterprise Linux 7",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "defaultStatus": "affected",
          "packageName": "samba-winbind",
          "product": "Red Hat Enterprise Linux 8",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "defaultStatus": "affected",
          "packageName": "samba-winbind",
          "product": "Red Hat Enterprise Linux 9",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "This issue was discovered by Runar Lundgren (Red Hat)."
        }
      ],
      "datePublic": "2026-07-14T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in samba\u0027s pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account\u0027s home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Moderate"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 6.1,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-732",
              "description": "Incorrect Permission Assignment for Critical Resource",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-15T12:33:04.688Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-15779"
        },
        {
          "name": "RHBZ#2499991",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2499991"
        },
        {
          "url": "https://gitlab.com/samba-team/samba/-/blob/samba-4.19.4/nsswitch/pam_winbind.c"
        },
        {
          "url": "https://gitlab.com/samba-team/samba/-/blob/samba-4.23.5/nsswitch/pam_winbind.c#L1622"
        },
        {
          "url": "https://gitlab.com/samba-team/samba/-/blob/samba-4.24.3/nsswitch/pam_winbind.c#L1590"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-05-21T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-07-14T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation",
      "workarounds": [
        {
          "lang": "en",
          "value": "Do not enable mkhomedir in pam_winbind.conf on systems where any account (including system accounts) may resolve to a home directory of / or another sensitive system path."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-732: Incorrect Permission Assignment for Critical Resource"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-15779",
    "datePublished": "2026-07-15T12:33:04.688Z",
    "dateReserved": "2026-07-14T18:33:36.712Z",
    "dateUpdated": "2026-07-15T13:04:49.311Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-15779\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2026-07-15T13:17:03.650\",\"lastModified\":\"2026-07-15T18:20:21.237\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A flaw was found in samba\u0027s pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account\u0027s home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.\"}],\"affected\":[{\"source\":\"secalert@redhat.com\",\"affectedData\":[{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 10\",\"defaultStatus\":\"affected\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"samba-winbind\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:10\"]},{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 6\",\"defaultStatus\":\"unknown\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"samba-winbind\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:6\"]},{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 7\",\"defaultStatus\":\"affected\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"samba-winbind\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:7\"]},{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 8\",\"defaultStatus\":\"affected\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"samba-winbind\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:8\"]},{\"vendor\":\"Red Hat\",\"product\":\"Red Hat Enterprise Linux 9\",\"defaultStatus\":\"affected\",\"collectionURL\":\"https://access.redhat.com/downloads/content/package-browser/\",\"packageName\":\"samba-winbind\",\"cpes\":[\"cpe:/o:redhat:enterprise_linux:9\"]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H\",\"baseScore\":6.1,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":4.2}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-15T13:04:26.614098Z\",\"id\":\"CVE-2026-15779\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-732\"}]}],\"references\":[{\"url\":\"https://access.redhat.com/security/cve/CVE-2026-15779\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=2499991\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://gitlab.com/samba-team/samba/-/blob/samba-4.19.4/nsswitch/pam_winbind.c\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://gitlab.com/samba-team/samba/-/blob/samba-4.23.5/nsswitch/pam_winbind.c#L1622\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://gitlab.com/samba-team/samba/-/blob/samba-4.24.3/nsswitch/pam_winbind.c#L1590\",\"source\":\"secalert@redhat.com\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-15T13:06:57+00:00",
      "cve": "CVE-2026-15779",
      "id": "CVE-2026-15779",
      "initial_release_date": "2026-07-14T00:00:00+00:00",
      "product_status:known_affected": "5",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-15779.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"cna\": {\"title\": \"Samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation\", \"metrics\": [{\"other\": {\"content\": {\"value\": \"Moderate\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}, \"type\": \"Red Hat severity rating\"}}, {\"cvssV3_1\": {\"attackComplexity\": \"LOW\", \"attackVector\": \"LOCAL\", \"availabilityImpact\": \"HIGH\", \"baseScore\": 6.1, \"baseSeverity\": \"MEDIUM\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"LOW\", \"privilegesRequired\": \"LOW\", \"scope\": \"UNCHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H\", \"version\": \"3.1\"}, \"format\": \"CVSS\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"A flaw was found in samba\u0027s pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account\u0027s home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.\"}], \"affected\": [{\"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 10\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"packageName\": \"samba-winbind\", \"defaultStatus\": \"affected\", \"cpes\": [\"cpe:/o:redhat:enterprise_linux:10\"]}, {\"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 6\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"packageName\": \"samba-winbind\", \"defaultStatus\": \"unknown\", \"cpes\": [\"cpe:/o:redhat:enterprise_linux:6\"]}, {\"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 7\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"packageName\": \"samba-winbind\", \"defaultStatus\": \"affected\", \"cpes\": [\"cpe:/o:redhat:enterprise_linux:7\"]}, {\"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 8\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"packageName\": \"samba-winbind\", \"defaultStatus\": \"affected\", \"cpes\": [\"cpe:/o:redhat:enterprise_linux:8\"]}, {\"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"packageName\": \"samba-winbind\", \"defaultStatus\": \"affected\", \"cpes\": [\"cpe:/o:redhat:enterprise_linux:9\"]}], \"references\": [{\"url\": \"https://access.redhat.com/security/cve/CVE-2026-15779\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2499991\", \"name\": \"RHBZ#2499991\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://gitlab.com/samba-team/samba/-/blob/samba-4.19.4/nsswitch/pam_winbind.c\"}, {\"url\": \"https://gitlab.com/samba-team/samba/-/blob/samba-4.23.5/nsswitch/pam_winbind.c#L1622\"}, {\"url\": \"https://gitlab.com/samba-team/samba/-/blob/samba-4.24.3/nsswitch/pam_winbind.c#L1590\"}], \"datePublic\": \"2026-07-14T00:00:00.000Z\", \"problemTypes\": [{\"descriptions\": [{\"cweId\": \"CWE-732\", \"description\": \"Incorrect Permission Assignment for Critical Resource\", \"lang\": \"en\", \"type\": \"CWE\"}]}], \"x_redhatCweChain\": \"CWE-732: Incorrect Permission Assignment for Critical Resource\", \"workarounds\": [{\"lang\": \"en\", \"value\": \"Do not enable mkhomedir in pam_winbind.conf on systems where any account (including system accounts) may resolve to a home directory of / or another sensitive system path.\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-05-21T00:00:00.000Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-07-14T00:00:00.000Z\", \"value\": \"Made public.\"}], \"credits\": [{\"lang\": \"en\", \"value\": \"This issue was discovered by Runar Lundgren (Red Hat).\"}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-07-15T12:33:04.688Z\"}, \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-15779\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-15T13:04:26.614098Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-15T13:04:45.996Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-15779\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"redhat\", \"dateReserved\": \"2026-07-14T18:33:36.712Z\", \"datePublished\": \"2026-07-15T12:33:04.688Z\", \"dateUpdated\": \"2026-07-15T13:04:49.311Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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.