{"id":"CVE-2026-118679","kind":"vulnerability","aliases":["CVE-2026-118679"],"related":[],"title":"n8n: Slack Trigger webhook lets unauthenticated attackers steal Slack tokens","description":"n8n before 1.123.83, 2.41.4, and 2.42.1 contains a server-side request forgery vulnerability in the Slack Trigger webhook that allows unauthenticated attackers to exfiltrate Slack tokens by bypassing signature verification when no signing secret is set. Attackers who know the webhook URL can name a file to download, causing the node to send the workspace access token to an attacker host and return the response.","summary":"n8n's Slack Trigger webhook skips signature checks when no signing secret is set, so anyone who knows the webhook URL can make it fetch an attacker-chosen file. The request sends the Slack workspace access token to the attacker's host, which exposes that token.","severity":"high","cvss":7.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ai-tooling","n8n","self-hosted","slack","workflow-automation"],"not_affected_if":["managed-hosting","no-slack-trigger","signing-secret-set"],"how_to_check":"- Run `n8n --version` (or check the n8n image tag) and compare against `1.123.83`, `2.41.4` and `2.42.1`.\n- In each workflow, look for a Slack Trigger node and check whether a Slack signing secret is configured in its credentials.\n- Confirm whether the n8n webhook URLs are reachable from the internet.","fix":"- Upgrade n8n to `1.123.83` on the 1.x line, `2.41.4` on 2.41.x, or `2.42.1` on 2.42.x.\n- Set a Slack signing secret on every Slack Trigger node until the upgrade is done.\n- Rotate the Slack workspace access tokens used by n8n if the instance was exposed while unpatched.","status":"open","published_at":"2026-10-28T19:17:34+00:00","first_seen_at":"2026-10-28T19:34:55+00:00","triaged_at":"2026-10-28T19:36:00+00:00","updated_at":"2026-10-28T19:36:00+00:00","category":"ai-tooling","confidence":0.7,"triage":{"at":"2026-10-28T19:36:00Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade n8n to `1.123.83` on the 1.x line, `2.41.4` on 2.41.x, or `2.42.1` on 2.42.x.\n- Set a Slack signing secret on every Slack Trigger node until the upgrade is done.\n- Rotate the Slack workspace access tokens used by n8n if the instance was exposed while unpatched.","reach":"internet","title":"n8n: Slack Trigger webhook lets unauthenticated attackers steal Slack tokens","impact":"high","summary":"n8n's Slack Trigger webhook skips signature checks when no signing secret is set, so anyone who knows the webhook URL can make it fetch an attacker-chosen file. The request sends the Slack workspace access token to the attacker's host, which exposes that token.","category":"ai-tooling","nicknames":[],"who_cares":["n8n","self-hosted","slack","workflow-automation"],"confidence":0.7,"needs_auth":"no","worst_case":"Attackers steal Slack workspace access tokens without logging in.","analyst_note":"Check the NVD entry and n8n release notes for exact fixed versions and whether the signing-secret condition is the only trigger.","how_to_check":"- Run `n8n --version` (or check the n8n image tag) and compare against `1.123.83`, `2.41.4` and `2.42.1`.\n- In each workflow, look for a Slack Trigger node and check whether a Slack signing secret is configured in its credentials.\n- Confirm whether the n8n webhook URLs are reachable from the internet.","needs_analyst":true,"not_affected_if":["no-slack-trigger","signing-secret-set","managed-hosting"],"who_is_affected":"Teams running self-hosted n8n with a Slack Trigger node whose webhook is reachable from the internet and whose signing secret is not set. Instances without a Slack Trigger, or with a signing secret configured, are not described as exposed by the sources. Managed n8n hosting is handled by the vendor, so those teams should confirm the vendor has applied the fix.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.00071,"input_tokens":3368,"output_tokens":746,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-118679':13A,16A '-2026':12A,15A '1.123.83':77C '2.41.4':78C '2.42.1':80C 'access':64B,131C 'ai':18B 'ai-tool':17B 'allow':95C 'anyon':43B 'attack':7A,55B,68B,97C,112C,135C 'attacker-chosen':54B 'autom':27B 'bypass':103C 'caus':124C 'check':35B 'chosen':56B 'contain':81C 'cve':11A,14A 'download':123C 'exfiltr':99C 'expos':72B 'fetch':52B 'file':57B,121C 'forgeri':87C 'host':23B,70B,136C 'know':45B,114C 'let':5A 'make':50B 'n8n':1A,20B,28B,75C 'name':119C 'node':126C 'request':59B,86C 'respons':140C 'return':138C 'secret':39B,109C 'self':22B 'self-host':21B 'send':60B,128C 'server':84C 'server-sid':83C 'set':41B,111C 'side':85C 'sign':38B,108C 'signatur':34B,104C 'skip':33B 'slack':2A,9A,24B,30B,62B,91C,100C 'steal':8A 'token':10A,65B,74B,101C,132C 'tool':19B 'trigger':3A,31B,92C 'unauthent':6A,96C 'url':48B,117C 'verif':105C 'vulner':88C 'webhook':4A,32B,47B,93C,116C 'workflow':26B 'workflow-autom':25B 'workspac':63B,130C","nicknames":[],"mitigations":[],"who_affected":"Teams running self-hosted n8n with a Slack Trigger node whose webhook is reachable from the internet and whose signing secret is not set. Instances without a Slack Trigger, or with a signing secret configured, are not described as exposed by the sources. Managed n8n hosting is handled by the vendor, so those teams should confirm the vendor has applied the fix.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T19:17:34+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:L/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-2026-118679","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118679","severity":null,"published_at":"2026-10-28T19:17:34+00:00","modified_at":"2026-10-28T19:17:34+00:00","first_seen_at":"2026-10-28T19:34:55+00:00","fetched_at":"2026-10-28T19:34:55+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"}