{"api_version":"1","generated_at":"2026-11-13T20:30:02+00:00","cve":"CVE-2026-129126","urls":{"html":"https://cve.report/CVE-2026-129126","api":"https://cve.report/api/cve/CVE-2026-129126.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-129126","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-129126"},"summary":{"title":"C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packet Decoding","description":"C-Kermit before 11.1.515 contains a heap buffer overflow vulnerability in putsrv() in ckcfns.c that allows malicious peers to write past the srvcmd buffer by sending crafted packets. Attackers can use Kermit repeat-count compression in server command, GET, or file-header packets to write attacker-chosen bytes beyond the heap buffer on servers or receiving instances.","state":"PUBLISHED","assigner":"VulnCheck","published_at":"2026-11-13 17:17:29","updated_at":"2026-11-13 17:17:29"},"problem_types":["CWE-122","CWE-122 Heap-based Buffer Overflow"],"metrics":[{"version":"4.0","source":"disclosure@vulncheck.com","type":"Secondary","score":"9.2","severity":"CRITICAL","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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","data":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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","baseScore":9.2,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"9.2","severity":"CRITICAL","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","data":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":9.2,"baseSeverity":"CRITICAL","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH"}},{"version":"3.1","source":"disclosure@vulncheck.com","type":"Primary","score":"8.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"8.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://github.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897","name":"https://github.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897","refsource":"disclosure@vulncheck.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.vulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding","name":"https://www.vulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding","refsource":"disclosure@vulncheck.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c#L461","name":"https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c#L461","refsource":"disclosure@vulncheck.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p","name":"https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p","refsource":"disclosure@vulncheck.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515","name":"https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515","refsource":"disclosure@vulncheck.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-129126","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-129126","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"OpenKermit","product":"C-Kermit","version":"affected 11.1.515 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"John Goerzen","lang":"en"},{"source":"CNA","value":"John Goerzen","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","packageURL":"pkg:github/OpenKermit/ckermit","product":"C-Kermit","vendor":"OpenKermit","versions":[{"lessThan":"11.1.515","status":"affected","version":"0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"John Goerzen"},{"lang":"en","type":"remediation developer","value":"John Goerzen"}],"datePublic":"2026-10-31T00:00:00.000Z","descriptions":[{"lang":"en","value":"C-Kermit before 11.1.515 contains a heap buffer overflow vulnerability in putsrv() in ckcfns.c that allows malicious peers to write past the srvcmd buffer by sending crafted packets. Attackers can use Kermit repeat-count compression in server command, GET, or file-header packets to write attacker-chosen bytes beyond the heap buffer on servers or receiving instances."}],"metrics":[{"cvssV4_0":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":9.2,"baseSeverity":"CRITICAL","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH"},"format":"CVSS"},{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-122","description":"Heap-based Buffer Overflow","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-13T16:23:41.944Z","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck"},"references":[{"name":"GitHub Security Advisory (GHSA-c5px-7h4c-gj8p)","tags":["vendor-advisory"],"url":"https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p"},{"tags":["patch"],"url":"https://github.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897"},{"name":"C-Kermit v11.1.515 Release Notes","tags":["release-notes"],"url":"https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515"},{"tags":["technical-description"],"url":"https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c#L461"},{"name":"VulnCheck Advisory: C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packet Decoding","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding"}],"title":"C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packet Decoding","x_generator":{"engine":"vulncheck-endgame"}}},"cveMetadata":{"assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","assignerShortName":"VulnCheck","cveId":"CVE-2026-129126","datePublished":"2026-11-13T16:23:41.944Z","dateReserved":"2026-11-13T16:01:01.879Z","dateUpdated":"2026-11-13T16:23:41.944Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-13 17:17:29","lastModifiedDate":"2026-11-13 17:17:29","problem_types":["CWE-122","CWE-122 Heap-based Buffer Overflow"],"metrics":{"cvssMetricV40":[{"source":"disclosure@vulncheck.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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","baseScore":9.2,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"disclosure@vulncheck.com","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.2,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"129126","Ordinal":"1","Title":"C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packe","CVE":"CVE-2026-129126","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"129126","Ordinal":"1","NoteData":"C-Kermit before 11.1.515 contains a heap buffer overflow vulnerability in putsrv() in ckcfns.c that allows malicious peers to write past the srvcmd buffer by sending crafted packets. Attackers can use Kermit repeat-count compression in server command, GET, or file-header packets to write attacker-chosen bytes beyond the heap buffer on servers or receiving instances.","Type":"Description","Title":"C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packe"}]}}}