{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-107708", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-10-08T16:52:24.550Z", "datePublished": "2026-10-08T20:15:53.534Z", "dateUpdated": "2026-10-08T20:15:53.534Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-08T20:15:53.534Z"}, "datePublic": "2026-05-19T00:00:00.000Z", "title": "MIT krb5 through 1.22.2 KDC NULL Pointer Dereference via S4U2Proxy PAC", "descriptions": [{"lang": "en", "value": "MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "NULL Pointer Dereference", "cweId": "CWE-476", "type": "CWE"}]}], "affected": [{"vendor": "MIT", "product": "krb5", "collectionURL": "https://github.com/krb5/krb5", "packageURL": "pkg:github/krb5/krb5", "repo": "https://github.com/krb5/krb5", "defaultStatus": "unaffected", "versions": [{"version": "0", "lessThanOrEqual": "1.22.2", "status": "affected", "versionType": "custom"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*", "versionEndIncluding": "1.22.2"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 6.9, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "baseScore": 4.9, "baseSeverity": "MEDIUM"}}], "references": [{"url": "https://github.com/krb5/krb5/pull/1510", "tags": ["issue-tracking", "patch"], "name": "Pull Request #1510"}, {"url": "https://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7", "tags": ["patch"], "name": "Patch Commit"}, {"url": "https://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86d", "tags": ["patch"]}, {"url": "https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676", "tags": ["technical-description"]}, {"url": "https://github.com/krb5/krb5", "tags": ["product"]}, {"name": "VulnCheck Advisory: MIT krb5 through 1.22.2 KDC NULL Pointer Dereference via S4U2Proxy PAC", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pac"}], "credits": [{"lang": "en", "value": "Tristan Madani", "type": "finder"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://github.com/krb5/krb5", "defaultStatus": "unaffected", "packageURL": "pkg:github/krb5/krb5", "product": "krb5", "repo": "https://github.com/krb5/krb5", "vendor": "MIT", "versions": [{"lessThanOrEqual": "1.22.2", "status": "affected", "version": "0", "versionType": "custom"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication."}], "id": "CVE-2026-107708", "lastModified": "2026-10-08T21:33:42.423", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 4.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.2, "impactScore": 3.6, "source": "disclosure@vulncheck.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "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": "HIGH", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}]}, "published": "2026-10-08T21:17:52.223", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/krb5/krb5"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86d"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/krb5/krb5/pull/1510"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pac"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "disclosure@vulncheck.com", "type": "Primary"}]}

{"bugzilla": {"description": "krb5: krb5: Denial of Service via malformed PAC in S4U2Proxy requests", "id": "2548262", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2548262"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["A flaw was found in krb5. This vulnerability allows a compromised or malicious cross-realm trusted Key Distribution Center (KDC) to cause a Denial of Service (DoS). By sending an S4U2Proxy delegation request containing a malformed client name within a Privilege Attribute Certificate (PAC), an attacker can trigger a NULL pointer dereference that crashes the KDC daemon, interrupting authentication services."], "name": "CVE-2026-107708", "package_state": [{"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Fix deferred", "package_name": "migration-toolkit-virtualization/mtv-virt-v2v-rhel10", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:certifications:9", "fix_state": "Fix deferred", "package_name": "rhcertification/redhat-certification-baremetal", "product_name": "Red Hat Certification Program for Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:certifications:9", "fix_state": "Fix deferred", "package_name": "rhcertification/redhat-certification-system-ai-10", "product_name": "Red Hat Certification Program for Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:certifications:9", "fix_state": "Fix deferred", "package_name": "rhcertification/redhat-certification-system-ai-9", "product_name": "Red Hat Certification Program for Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "krb5", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "rhel10-eus/rhel-10.0-bootc", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "rhel10-eus/rhel-10.2-bootc", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "rhel10/rhel-bootc", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "krb5", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "krb5", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "krb5", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "krb5", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "rhel9-eus/rhel-9.6-bootc", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "rhel9-eus/rhel-9.8-bootc", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "rhel9/rhel-bootc", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "krb5", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift4/driver-toolkit-rhel9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift4/ose-ironic-machine-os-downloader-rhel9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openstack:18.0", "fix_state": "Fix deferred", "package_name": "rhoso/openstack-nova-compute-rhel9", "product_name": "Red Hat OpenStack Platform 18.0"}], "public_date": "2026-10-08T20:15:53Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-107708\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-107708\nhttps://github.com/krb5/krb5\nhttps://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676\nhttps://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86d\nhttps://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7\nhttps://github.com/krb5/krb5/pull/1510\nhttps://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pac"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,1.22.2]"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "krb5", "source": "cna", "vendor": "MIT"}, "product": "kerberos_5", "vendor": "mit"}], "created": "2026-10-08T21:30:18.742745+00:00", "updated": "2026-10-08T22:00:17.691347+00:00", "vendors": ["mit", "mit$PRODUCT$kerberos_5"]}