{"id":"CVE-2026-118237","kind":"vulnerability","aliases":["CVE-2026-118237"],"related":[],"title":"GitHub Enterprise Server: SSH re-key flaw leaks adjacent process memory","description":"An out-of-bounds read vulnerability was identified in GitHub Enterprise Server in the Git service (babeld). When proving possession of a host key, babeld's SSH implementation sized the session identifier by the current digest length rather than its own. An attacker with an account and SSH access could re-key to an algorithm with a longer hash, causing adjacent process memory to be signed and returned to the client, where a limited amount of it may be recoverable. This vulnerability affected all releases prior to 3.23 and was fixed in versions 3.22.3, 3.21.8, 3.20.10, and 3.19.14. This vulnerability was reported via the GitHub Bug Bounty program.","summary":"GitHub Enterprise Server's Git service (babeld) sized the SSH session identifier with the wrong digest length during host key proof, an out-of-bounds read. An authenticated user can re-key to an algorithm with a longer hash and get adjacent process memory signed and returned, where some of it may be recoverable.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["git","github-enterprise-server","runtime","self-hosted","ssh"],"not_affected_if":["fixed-version","github-com","no-ssh-access"],"how_to_check":"- Check the installed GitHub Enterprise Server version in the admin console or with `ghe-version` on the appliance\n- Confirm whether the instance is running a release prior to `3.23`","fix":"- Upgrade to `3.22.3` on the 3.22 line\n- Upgrade to `3.21.8` on the 3.21 line\n- Upgrade to `3.20.10` on the 3.20 line\n- Upgrade to `3.19.14` on the 3.19 line","status":"open","published_at":"2026-11-03T23:17:33+00:00","first_seen_at":"2026-11-03T23:45:14+00:00","triaged_at":"2026-11-03T23:45:47+00:00","updated_at":"2026-11-03T23:45:47+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-03T23:45:47Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade to `3.22.3` on the 3.22 line\n- Upgrade to `3.21.8` on the 3.21 line\n- Upgrade to `3.20.10` on the 3.20 line\n- Upgrade to `3.19.14` on the 3.19 line","reach":"network","title":"GitHub Enterprise Server: SSH re-key flaw leaks adjacent process memory","impact":"low","summary":"GitHub Enterprise Server's Git service (babeld) sized the SSH session identifier with the wrong digest length during host key proof, an out-of-bounds read. An authenticated user can re-key to an algorithm with a longer hash and get adjacent process memory signed and returned, where some of it may be recoverable.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["github-enterprise-server","self-hosted","ssh","git"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"adjacent process memory leaks to an authenticated user over SSH","analyst_note":"","how_to_check":"- Check the installed GitHub Enterprise Server version in the admin console or with `ghe-version` on the appliance\n- Confirm whether the instance is running a release prior to `3.23`","plain_action":"","needs_analyst":false,"not_affected_if":["github-com","no-ssh-access","fixed-version"],"who_is_affected":"Only GitHub Enterprise Server instances running releases before 3.23 are affected, and only through the Git service's SSH access. An attacker needs a user account with SSH access to the instance, so instances without SSH access for users are less exposed. Teams running GitHub.com or instances already on the fixed versions can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000741,"input_tokens":4249,"output_tokens":632,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-118237':15A,18A '-2026':14A,17A '3.19.14':184C '3.20.10':182C '3.21.8':181C '3.22.3':180C '3.23':174C 'access':134C 'account':131C 'adjac':10A,72B,147C 'affect':169C 'algorithm':65B,141C 'amount':161C 'attack':128C 'authent':57B 'babeld':35B,102C,110C 'bound':54B,89C 'bounti':193C 'bug':192C 'caus':146C 'client':157C 'could':135C 'current':120C 'cve':13A,16A 'digest':44B,121C 'enterpris':2A,22B,30B,96C 'fix':177C 'flaw':8A 'get':71B 'git':19B,33B,100C 'github':1A,21B,29B,95C,191C 'github-enterprise-serv':20B 'hash':69B,145C 'host':27B,47B,108C 'identifi':40B,93C,117C 'implement':113C 'key':7A,48B,62B,109C,138C 'leak':9A 'length':45B,122C 'limit':160C 'longer':68B,144C 'may':82B,164C 'memori':12A,74B,149C 'out-of-bound':51B,86C 'possess':105C 'prior':172C 'process':11A,73B,148C 'program':194C 'proof':49B 'prove':104C 'rather':123C 're':6A,61B,137C 're-key':5A,60B,136C 'read':55B,90C 'recover':84B,166C 'releas':171C 'report':188C 'return':77B,154C 'runtim':24B 'self':26B 'self-host':25B 'server':3A,23B,31B,97C 'servic':34B,101C 'session':39B,116C 'sign':75B,152C 'size':36B,114C 'ssh':4A,28B,38B,112C,133C 'user':58B 'version':179C 'via':189C 'vulner':91C,168C,186C 'wrong':43B","nicknames":[],"mitigations":[],"who_affected":"Only GitHub Enterprise Server instances running releases before 3.23 are affected, and only through the Git service's SSH access. An attacker needs a user account with SSH access to the instance, so instances without SSH access for users are less exposed. Teams running GitHub.com or instances already on the fixed versions can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["git","githubenterpriseserver","medium","runtime","selfhosted","ssh"],"campaign_type":null,"first_public_at":"2026-11-03T23:17:33+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/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":"product-cna@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118237","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118237","severity":null,"published_at":"2026-11-03T23:17:33+00:00","modified_at":"2026-11-03T23:17:33+00:00","first_seen_at":"2026-11-03T23:45:14+00:00","fetched_at":"2026-11-03T23:45:14+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}