{"id":"CVE-2026-129120","kind":"vulnerability","aliases":["CVE-2026-129120"],"related":[],"title":"C-Kermit: malicious server writes files without prompt, enabling code execution","description":"C-Kermit 11.0.506 before 11.1.515 contains a RECEIVE CONFIRM bypass vulnerability that allows malicious Kermit servers to write unrequested files without prompting by abusing recursive GET root computation in ckcfns.c. Attackers can send files such as .ssh/authorized_keys or shell startup files under the current directory, which rq_under_root() accepts silently, enabling persistent access or code execution.","summary":"C-Kermit 11.0.506 before 11.1.515 lets a malicious Kermit server write files to the client without asking the user, bypassing the RECEIVE CONFIRM check. An attacker can drop files such as .ssh/authorized_keys or shell startup files, which gives persistent access or code execution.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"C-Kermit","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["c-kermit","kermit","linux","other","unix"],"not_affected_if":["no-untrusted-kermit-servers"],"how_to_check":"- Check the installed C-Kermit version with `kermit -v` or the version banner shown on start-up\n- Treat any version below `11.1.515` as affected","fix":"- C-Kermit: `11.1.515`","status":"open","published_at":"2026-11-13T17:17:29+00:00","first_seen_at":"2026-11-13T17:48:00+00:00","triaged_at":"2026-11-13T17:49:06+00:00","updated_at":"2026-11-13T17:49:06+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-13T17:49:06Z","model":"claude-haiku-5-5","output":{"fix":"- C-Kermit: `11.1.515`","reach":"network","title":"C-Kermit: malicious server writes files without prompt, enabling code execution","impact":"high","summary":"C-Kermit 11.0.506 before 11.1.515 lets a malicious Kermit server write files to the client without asking the user, bypassing the RECEIVE CONFIRM check. An attacker can drop files such as .ssh/authorized_keys or shell startup files, which gives persistent access or code execution.","audience":"businesses","category":"other","nicknames":[],"who_cares":["c-kermit","kermit","linux","unix"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"Attacker writes startup files or authorized_keys, gaining persistent code execution","analyst_note":"Confirm user interaction and default configuration from the vendor advisory and release notes linked on github.com.","how_to_check":"- Check the installed C-Kermit version with `kermit -v` or the version banner shown on start-up\n- Treat any version below `11.1.515` as affected\n- unknown","plain_action":"","product_name":"C-Kermit","needs_analyst":true,"not_affected_if":["no-untrusted-kermit-servers"],"who_is_affected":"Teams that run C-Kermit 11.0.506 through versions before 11.1.515 and use it to receive files from remote Kermit servers are exposed. The sources do not say whether a non-default configuration is needed, so systems that never connect to untrusted Kermit servers are likely lower risk.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000763,"input_tokens":4683,"output_tokens":589,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-129120':15A,18A '-2026':14A,17A '11.0.506':32B,76C '11.1.515':34B,78C 'abus':97C 'accept':123C 'access':69B,127C 'allow':86C 'ask':46B 'attack':55B,104C 'bypass':49B,83C 'c':2A,20A,23B,30B,74C 'c-kermit':1A,19A,22B,29B,73C 'check':53B 'ckcfns.c':103C 'client':44B 'code':11A,71B,129C 'comput':101C 'confirm':52B,82C 'contain':79C 'current':117C 'cve':13A,16A 'directori':118C 'drop':57B 'enabl':10A,125C 'execut':12A,72B,130C 'file':7A,41B,58B,65B,93C,107C,114C 'get':99C 'give':67B 'kermit':3A,21A,24B,25B,31B,38B,75C,88C 'let':35B 'linux':26B 'malici':4A,37B,87C 'persist':68B,126C 'prompt':9A,95C 'receiv':51B,81C 'recurs':98C 'root':100C,122C 'rq':120C 'send':106C 'server':5A,39B,89C 'shell':63B,112C 'silent':124C 'ssh/authorized_keys':61B,110C 'startup':64B,113C 'unix':28B 'unrequest':92C 'user':48B 'vulner':84C 'without':8A,45B,94C 'write':6A,40B,91C","nicknames":[],"mitigations":[],"who_affected":"Teams that run C-Kermit 11.0.506 through versions before 11.1.515 and use it to receive files from remote Kermit servers are exposed. The sources do not say whether a non-default configuration is needed, so systems that never connect to untrusted Kermit servers are likely lower risk.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["ckermit"],"ptokens":["kermit"],"labels":["ckermit","kermit","linux","medium","other","unix","vendor"],"campaign_type":null,"search_a":"'-129120':15A,18A '-2026':14A,17A 'c':2A,20A 'c-kermit':1A,19A 'code':11A 'cve':13A,16A 'enabl':10A 'execut':12A 'file':7A 'kermit':3A,21A 'malici':4A 'prompt':9A 'server':5A 'without':8A 'write':6A","search_b":"'11.0.506':32B '11.1.515':34B 'access':69B 'ask':46B 'attack':55B 'bypass':49B 'c':23B,30B 'c-kermit':22B,29B 'check':53B 'client':44B 'code':71B 'confirm':52B 'drop':57B 'execut':72B 'file':41B,58B,65B 'give':67B 'kermit':24B,25B,31B,38B 'let':35B 'linux':26B 'malici':37B 'persist':68B 'receiv':51B 'server':39B 'shell':63B 'ssh/authorized_keys':61B 'startup':64B 'unix':28B 'user':48B 'without':45B 'write':40B","search_c":"'11.0.506':76C '11.1.515':78C 'abus':97C 'accept':123C 'access':127C 'allow':86C 'attack':104C 'bypass':83C 'c':74C 'c-kermit':73C 'ckcfns.c':103C 'code':129C 'comput':101C 'confirm':82C 'contain':79C 'current':117C 'directori':118C 'enabl':125C 'execut':130C 'file':93C,107C,114C 'get':99C 'kermit':75C,88C 'malici':87C 'persist':126C 'prompt':95C 'receiv':81C 'recurs':98C 'root':100C,122C 'rq':120C 'send':106C 'server':89C 'shell':112C 'silent':124C 'ssh/authorized_keys':110C 'startup':113C 'unrequest':92C 'vulner':84C 'without':94C 'write':91C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-10-31T01:21:24+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/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","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-129120","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-129120","severity":null,"published_at":"2026-11-13T17:17:29+00:00","modified_at":"2026-11-13T17:17:29+00:00","first_seen_at":"2026-11-13T17:48:00+00:00","fetched_at":"2026-11-13T17:48:00+00:00","note":null}],"documents":[{"id":148091,"url":"https://github.com/OpenKermit/ckermit/commit/49e04a5ccfa08706b1d7e51dce4059f4adce50f3","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":148076,"url":"https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515","title":"Release notes: github.com","kind":"release","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Release notes: github.com"},{"id":148089,"url":"https://github.com/OpenKermit/ckermit/security/advisories/GHSA-vhrv-7jrq-95qj","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-31T01:21:24+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":148094,"url":"https://www.vulncheck.com/advisories/c-kermit-11.0.506-before-11.1.515-receive-confirm-bypass-via-recursive-get","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}