{"id":"CVE-2026-121968","kind":"vulnerability","aliases":["CVE-2026-121968"],"related":[],"title":"Netrek-client-cow: out-of-bounds read lets a malicious server crash clients","description":"Netrek-client-cow through 3.3.3 contains an out-of-bounds read vulnerability in short.c handleSMessage() that allows malicious servers to crash clients via an unchecked m_recpt index. Attackers controlling a Netrek server or intercepting the plaintext TCP connection can send SP_S_MESSAGE packets with m_recpt of 36 or more, reading past players[] and shipnos to deny service.","summary":"Netrek-client-cow through 3.3.3 mishandles SP_S_MESSAGE packets in short.c, reading memory past the players array when the recipient index is 36 or more. An attacker running a Netrek server, or intercepting the plaintext TCP connection, can crash the client and deny service.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["games","netrek","netrek-client-cow","other"],"not_affected_if":["private-network","trusted-server-only"],"how_to_check":"- Check the installed Netrek-client-cow version against the affected range (through `3.3.3`).\n- Look for the `short.c` handleSMessage() code path if you build the client from source.","fix":"Patch linked at github.com; the fixed version is unknown from the sources.","status":"open","published_at":"2026-11-04T21:18:06+00:00","first_seen_at":"2026-11-04T21:49:18+00:00","triaged_at":"2026-11-04T21:51:00+00:00","updated_at":"2026-11-04T21:51:00+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-04T21:51:00Z","model":"claude-haiku-5-5","output":{"fix":"Patch linked at github.com; the fixed version is unknown from the sources.","reach":"network","title":"Netrek-client-cow: out-of-bounds read lets a malicious server crash clients","impact":"low","summary":"Netrek-client-cow through 3.3.3 mishandles SP_S_MESSAGE packets in short.c, reading memory past the players array when the recipient index is 36 or more. An attacker running a Netrek server, or intercepting the plaintext TCP connection, can crash the client and deny service.","audience":"developers","category":"other","nicknames":[],"who_cares":["netrek-client-cow","netrek","games"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"Client crashes, denying service to the player","analyst_note":"Confirm the fixed version from the linked GitHub patch and the VulnCheck advisory at www.vulncheck.com.","how_to_check":"- Check the installed Netrek-client-cow version against the affected range (through `3.3.3`).\n- Look for the `short.c` handleSMessage() code path if you build the client from source.","plain_action":"","needs_analyst":true,"not_affected_if":["trusted-server-only","private-network"],"who_is_affected":"Players and operators who connect the Netrek-client-cow client to Netrek servers, especially over untrusted networks or plaintext TCP. Clients that only connect to trusted servers on a private network face less exposure. The sources do not say whether a fixed version exists beyond a linked patch.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000703,"input_tokens":4211,"output_tokens":564,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121968':18A,21A '-2026':17A,20A '3.3.3':33B,79C '36':52B,125C 'allow':92C 'array':46B 'attack':56B,104C 'bound':8A,85C 'client':3A,15A,26B,30B,70B,76C,97C 'connect':66B,114C 'contain':80C 'control':105C 'cow':4A,27B,31B,77C 'crash':14A,68B,96C 'cve':16A,19A 'deni':72B,134C 'game':22B 'handlesmessag':90C 'index':50B,103C 'intercept':62B,110C 'let':10A 'm':101C,122C 'malici':12A,93C 'memori':42B 'messag':37B,119C 'mishandl':34B 'netrek':2A,23B,25B,29B,59B,75C,107C 'netrek-client-cow':1A,24B,28B,74C 'out-of-bound':5A,82C 'packet':38B,120C 'past':43B,129C 'plaintext':64B,112C 'player':45B,130C 'read':9A,41B,86C,128C 'recipi':49B 'recpt':102C,123C 'run':57B 'send':116C 'server':13A,60B,94C,108C 'servic':73B,135C 'shipno':132C 'short.c':40B,89C 'sp':35B,117C 'tcp':65B,113C 'uncheck':100C 'via':98C 'vulner':87C","nicknames":[],"mitigations":[],"who_affected":"Players and operators who connect the Netrek-client-cow client to Netrek servers, especially over untrusted networks or plaintext TCP. Clients that only connect to trusted servers on a private network face less exposure. The sources do not say whether a fixed version exists beyond a linked patch.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["games","high","netrek","netrekclientcow","other"],"campaign_type":null,"first_public_at":"2026-11-04T21:18:06+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121968","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121968","severity":null,"published_at":"2026-11-04T21:18:06+00:00","modified_at":"2026-11-04T21:18:06+00:00","first_seen_at":"2026-11-04T21:49:18+00:00","fetched_at":"2026-11-04T21:49:18+00:00","note":null}],"documents":[{"id":70631,"url":"https://github.com/quozl/netrek-client-cow/commit/fb322e74abee3b0b76a9c5a31df6aab5585d3127","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":70632,"url":"https://www.vulncheck.com/advisories/netrek-client-cow-through-3.3.3-out-of-bounds-read-via-sp-s-message-packets","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"}],"exploit_sources":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}