{"id":"CVE-2026-121603","kind":"vulnerability","aliases":["CVE-2026-121603"],"related":[],"title":"Solanum IRC server: overlong kill reason overflows buffer, risks code execution","description":"Solanum before commit 2ea1382 contains a buffer overflow vulnerability in ms_kill() that allows malicious linked servers to corrupt memory by sending an overlong kill reason. Attackers controlling a rogue or compromised peer server can send a reason exceeding KILLLEN that overflows a static 512-byte buffer, crashing the ircd or potentially achieving remote code execution.","summary":"Solanum, an IRC server daemon, has a buffer overflow in its ms_kill() handler: a linked server sending a kill reason longer than KILLLEN overflows a static 512-byte buffer. The result is a crash of the ircd, and possibly remote code execution.","severity":"high","cvss":8.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["irc","runtime","self-hosted","solanum"],"not_affected_if":["newer-commit","no-server-links","trusted-peers-only"],"how_to_check":"- Check the installed Solanum version or git commit and compare it with commit `2ea1382`; builds before that commit are exposed.\n- Check whether the server accepts server-to-server links from peers you do not fully control.","fix":"- Solanum: move to a build that includes commit `2ea1382` or later (the patch linked from the sources).","status":"open","published_at":"2026-11-03T17:18:11+00:00","first_seen_at":"2026-11-03T17:21:56+00:00","triaged_at":"2026-11-03T17:23:56+00:00","updated_at":"2026-11-03T17:23:56+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-03T17:23:56Z","model":"claude-haiku-5-5","output":{"fix":"- Solanum: move to a build that includes commit `2ea1382` or later (the patch linked from the sources).","reach":"network","title":"Solanum IRC server: overlong kill reason overflows buffer, risks code execution","impact":"high","summary":"Solanum, an IRC server daemon, has a buffer overflow in its ms_kill() handler: a linked server sending a kill reason longer than KILLLEN overflows a static 512-byte buffer. The result is a crash of the ircd, and possibly remote code execution.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["solanum","irc","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"Remote code execution on the IRC server via a rogue linked peer","analyst_note":"Confirm the exploitability and whether code execution is realistic; the sources give only the NVD description and a patch link, so check the linked patch and the VulnCheck advisory.","how_to_check":"- Check the installed Solanum version or git commit and compare it with commit `2ea1382`; builds before that commit are exposed.\n- Check whether the server accepts server-to-server links from peers you do not fully control.","plain_action":"","needs_analyst":true,"not_affected_if":["no-server-links","trusted-peers-only","newer-commit"],"who_is_affected":"Only servers running Solanum before commit 2ea1382 are exposed, and the attack needs a linked server under attacker control, a rogue or compromised peer. Networks that link only to fully trusted servers face much less risk. Teams that run their own IRC network should look at their server links.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.00072,"input_tokens":4197,"output_tokens":600,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121603':14A,17A '-2026':13A,16A '2ea1382':70C '512':51B,111C 'achiev':119C 'allow':80C 'attack':93C 'buffer':8A,31B,53B,73C,113C 'byte':52B,112C 'code':10A,65B,121C 'commit':69C 'compromis':98C 'contain':71C 'control':94C 'corrupt':85C 'crash':58B,114C 'cve':12A,15A 'daemon':28B 'exceed':105C 'execut':11A,66B,122C 'handler':37B 'host':22B 'irc':2A,18B,26B 'ircd':61B,116C 'kill':5A,36B,43B,78C,91C 'killlen':47B,106C 'link':39B,82C 'longer':45B 'malici':81C 'memori':86C 'ms':35B,77C 'overflow':7A,32B,48B,74C,108C 'overlong':4A,90C 'peer':99C 'possibl':63B 'potenti':118C 'reason':6A,44B,92C,104C 'remot':64B,120C 'result':55B 'risk':9A 'rogu':96C 'runtim':19B 'self':21B 'self-host':20B 'send':41B,88C,102C 'server':3A,27B,40B,83C,100C 'solanum':1A,23B,24B,67C 'static':50B,110C 'vulner':75C","nicknames":[],"mitigations":[],"who_affected":"Only servers running Solanum before commit 2ea1382 are exposed, and the attack needs a linked server under attacker control, a rogue or compromised peer. Networks that link only to fully trusted servers face much less risk. Teams that run their own IRC network should look at their server links.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","irc","runtime","selfhosted","solanum"],"first_public_at":"2026-11-03T17:18:11+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/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-2026-121603","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121603","severity":null,"published_at":"2026-11-03T17:18:11+00:00","modified_at":"2026-11-03T17:18:11+00:00","first_seen_at":"2026-11-03T17:21:56+00:00","fetched_at":"2026-11-03T17:21:56+00:00","note":null}],"documents":[{"id":59257,"url":"https://github.com/solanum-ircd/solanum/commit/2ea1382e4262b212a91034258c466f0f6754cd61","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":59258,"url":"https://www.vulncheck.com/advisories/solanum-before-commit-2ea1382-buffer-overflow-via-server-to-server-kill-handler","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"}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}