{"id":"CVE-2026-114730","kind":"vulnerability","aliases":["CVE-2026-114730"],"related":[],"title":"Roundcube Webmail: SSRF filter bypass via NAT64 IPv6 addresses reaches internal hosts","description":"Roundcube Webmail 1.6.14 before 1.6.20 and 1.7.0 before 1.7.5 is affected by a server-side request forgery filter bypass. The network blocklist used by rcube_utils::is_local_url() omitted the RFC 6052 NAT64 prefix 64:ff9b::/96, the RFC 8215 local-use NAT64 prefix 64:ff9b:1::/48 and the unspecified address ::/128, so URLs such as http://[64:ff9b::7f00:1]/ passed the filter and reached loopback, link-local and cloud metadata addresses. Upstream fixed this in the commit “Fix SSRF filter (is_local_url()) bypass via NAT64 64:ff9b::/96”.","summary":"Roundcube's check for local URLs misses the NAT64 prefixes 64:ff9b::/96 and 64:ff9b:1::/48 and the unspecified address ::/128, so IPv6 URLs like http://[64:ff9b::7f00:1]/ pass. The server can then be made to request loopback, link-local and cloud metadata addresses.","severity":"high","cvss":7.2,"epss":0.00312,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["other","php","roundcube","self-hosted","webmail"],"not_affected_if":["patched-1.6.20-or-later","patched-1.7.5-or-later"],"how_to_check":"- Check the installed Roundcube version: it is affected if it is `1.6.14` to `1.6.19`, or `1.7.0` to `1.7.4`.\n- Confirm whether the installation is running the upstream commit “Fix SSRF filter (is_local_url()) bypass via NAT64 64:ff9b::/96”.","fix":"- Upgrade the 1.6 line to `1.6.20` or later.\n- Upgrade the 1.7 line to `1.7.5` or later.","status":"open","published_at":"2026-10-22T03:16:38+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","triaged_at":"2026-10-25T03:28:02+00:00","updated_at":"2026-10-25T03:28:02+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-10-25T03:28:02Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade the 1.6 line to `1.6.20` or later.\n- Upgrade the 1.7 line to `1.7.5` or later.","reach":"internet","title":"Roundcube Webmail: SSRF filter bypass via NAT64 IPv6 addresses reaches internal hosts","impact":"high","summary":"Roundcube's check for local URLs misses the NAT64 prefixes 64:ff9b::/96 and 64:ff9b:1::/48 and the unspecified address ::/128, so IPv6 URLs like http://[64:ff9b::7f00:1]/ pass. The server can then be made to request loopback, link-local and cloud metadata addresses.","category":"other","nicknames":[],"who_cares":["roundcube","webmail","self-hosted","php"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Server requests internal services and cloud metadata endpoints","analyst_note":"","how_to_check":"- Check the installed Roundcube version: it is affected if it is `1.6.14` to `1.6.19`, or `1.7.0` to `1.7.4`.\n- Confirm whether the installation is running the upstream commit “Fix SSRF filter (is_local_url()) bypass via NAT64 64:ff9b::/96”.","needs_analyst":false,"not_affected_if":["patched-1.6.20-or-later","patched-1.7.5-or-later"],"who_is_affected":"Roundcube Webmail installations on the affected version ranges are exposed, because the flaw sits in the URL filter that the server uses before fetching remote content. Systems running on cloud hosts with instance metadata endpoints deserve the most attention, since those are the targets the bypass reaches. Installations already on `1.6.20`, `1.7.5` or later can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.0013,"input_tokens":3529,"output_tokens":1895,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-114730':15A,18A '-2026':14A,17A '/128':48B,129C '/48':43B,124C '/96':38B,112C,168C '1':42B,56B,123C,137C '1.6.14':76C '1.6.20':78C '1.7.0':80C '1.7.5':82C '6052':107C '64':36B,40B,53B,110C,121C,134C,166C '7f00':55B,136C '8215':115C 'address':9A,47B,73B,128C,150C 'affect':84C 'blocklist':96C 'bypass':5A,93C,163C 'check':28B 'cloud':71B,148C 'commit':156C 'cve':13A,16A 'ff9b':37B,41B,54B,111C,122C,135C,167C 'filter':4A,92C,140C,159C 'fix':152C,157C 'forgeri':91C 'host':12A,24B 'intern':11A 'ipv6':8A,50B 'like':52B 'link':68B,145C 'link-loc':67B,144C 'local':30B,69B,102C,117C,146C,161C 'local-us':116C 'loopback':66B,143C 'made':63B 'metadata':72B,149C 'miss':32B 'nat64':7A,34B,108C,119C,165C 'network':95C 'omit':104C 'pass':57B,138C 'php':20B 'prefix':35B,109C,120C 'rcube':99C 'reach':10A,142C 'request':65B,90C 'rfc':106C,114C 'roundcub':1A,21B,26B,74C 'self':23B 'self-host':22B 'server':59B,88C 'server-sid':87C 'side':89C 'ssrf':3A,158C 'unspecifi':46B,127C 'upstream':151C 'url':31B,51B,103C,131C,162C 'use':97C,118C 'util':100C 'via':6A,164C 'webmail':2A,25B,75C","nicknames":[],"mitigations":[],"who_affected":"Roundcube Webmail installations on the affected version ranges are exposed, because the flaw sits in the URL filter that the server uses before fetching remote content. Systems running on cloud hosts with instance metadata endpoints deserve the most attention, since those are the targets the bypass reaches. Installations already on `1.6.20`, `1.7.5` or later can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T03:16:38+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N","cvss_by":"cve@mitre.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-114730","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114730","severity":null,"published_at":"2026-10-22T03:16:38+00:00","modified_at":"2026-10-22T16:45:49+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-114730","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-114730","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:51+00:00","fetched_at":"2026-10-24T07:15:51+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"}