CVE-2026-11850 (GCVE-0-2026-11850)
Vulnerability from cvelistv5
Published
2026-06-11 09:49
Modified
2026-10-31 15:50
Severity ?
5.0 (Medium) - CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
CWE
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Summary
An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.
References
https://access.redhat.com/errata/RHSA-2026:25520 vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-11850 vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2459970 issue-tracking, x_refsource_REDHAT
Impacted products
Vendor Product Version
Red Hat Red Hat Hardened Images Unaffected: 1.22.2-8.hum1   < *
    cpe:/a:redhat:hummingbird:1
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-11850",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-11T12:35:21.860008Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-11T12:37:05.721Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "cpes": [
            "cpe:/a:redhat:hummingbird:1"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5-main",
          "product": "Red Hat Hardened Images",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "1.22.2-8.hum1",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "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": "affected",
          "packageName": "krb5",
          "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": "krb5",
          "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": "krb5",
          "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": "krb5",
          "product": "Red Hat Enterprise Linux 9",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:openshift:4"
          ],
          "defaultStatus": "affected",
          "packageName": "openshift/ose-rhel-coreos-8",
          "product": "Red Hat OpenShift Container Platform 4",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:openshift:4"
          ],
          "defaultStatus": "affected",
          "packageName": "openshift/ose-rhel-coreos-9",
          "product": "Red Hat OpenShift Container Platform 4",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:openshift:5"
          ],
          "defaultStatus": "affected",
          "packageName": "openshift/ose-rhel-coreos-9",
          "product": "Red Hat OpenShift Container Platform 5",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank Sebasti\u00e1n Alba Vives for reporting this issue."
        }
      ],
      "datePublic": "2026-06-10T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Moderate"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-191",
              "description": "Integer Underflow (Wrap or Wraparound)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-31T15:50:37.499Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "name": "RHSA-2026:25520",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2026:25520"
        },
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-11850"
        },
        {
          "name": "RHBZ#2459970",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2459970"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-04-21T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-06-10T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read",
      "workarounds": [
        {
          "lang": "en",
          "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-191: Integer Underflow (Wrap or Wraparound)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-11850",
    "datePublished": "2026-06-11T09:49:07.726Z",
    "dateReserved": "2026-06-10T08:12:34.560Z",
    "dateUpdated": "2026-10-31T15:50:37.499Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-11850\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-11T12:35:21.860008Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-11T12:36:51.179Z\"}}], \"cna\": {\"title\": \"Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read\", \"credits\": [{\"lang\": \"en\", \"value\": \"Red Hat would like to thank Sebasti\\u00e1n Alba Vives for reporting this issue.\"}], \"metrics\": [{\"other\": {\"type\": \"Red Hat severity rating\", \"content\": {\"value\": \"Moderate\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}}}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"HIGH\", \"confidentialityImpact\": \"LOW\"}}], \"affected\": [{\"cpes\": [\"cpe:/a:redhat:hummingbird:1\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Hardened Images\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"1.22.2-8.hum1\", \"lessThan\": \"*\", \"versionType\": \"rpm\"}], \"packageName\": \"krb5-main\", \"collectionURL\": \"https://catalog.redhat.com/software/containers/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:10\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 10\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:6\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 6\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:7\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 7\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:8\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 8\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:9\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 9\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:openshift:4\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat OpenShift Container Platform 4\", \"packageName\": \"openshift/ose-rhel-coreos-8\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:openshift:4\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat OpenShift Container Platform 4\", \"packageName\": \"openshift/ose-rhel-coreos-9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:openshift:5\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat OpenShift Container Platform 5\", \"packageName\": \"openshift/ose-rhel-coreos-9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-04-21T00:00:00.000Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-06-10T00:00:00.000Z\", \"value\": \"Made public.\"}], \"datePublic\": \"2026-06-10T00:00:00.000Z\", \"references\": [{\"url\": \"https://access.redhat.com/errata/RHSA-2026:25520\", \"name\": \"RHSA-2026:25520\", \"tags\": [\"vendor-advisory\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://access.redhat.com/security/cve/CVE-2026-11850\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2459970\", \"name\": \"RHBZ#2459970\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.\"}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-191\", \"description\": \"Integer Underflow (Wrap or Wraparound)\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-10-31T15:50:37.499Z\"}, \"x_redhatCweChain\": \"CWE-191: Integer Underflow (Wrap or Wraparound)\"}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-11850\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-31T15:50:37.499Z\", \"dateReserved\": \"2026-06-10T08:12:34.560Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-06-11T09:49:07.726Z\", \"assignerShortName\": \"redhat\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.