{"id":"CVE-2026-123558","kind":"vulnerability","aliases":["CVE-2026-123558"],"related":[],"title":"Zebra zebrad: malicious peer can stall checkpoint sync until restart","description":"Zebra zebrad before 7.0.0 contains a denial of service vulnerability that allows a malicious peer to stall checkpoint sync by cancelling the verifier rewind after a failed commit. Attackers can serve a forged block with altered authorizing data plus a restart-triggering block, leaving the verifier rejecting honest blocks until restart.","summary":"Zebra's zebrad node, before 7.0.0, can be stalled by a malicious peer that serves a forged block with altered authorizing data followed by a restart-triggering block. The verifier then rejects honest blocks until the node restarts, so the node stops syncing and denial of service results.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","self-hosted","zcash","zebrad"],"not_affected_if":["zebrad-7.0.0-or-later"],"how_to_check":"- Check the zebrad version with `zebrad --version`; versions below `7.0.0` are in the affected range.\n- Look for checkpoint sync stalls in node logs after peer connections.","fix":"- `zebrad` moves to `7.0.0` or later, per the NVD description.","status":"open","published_at":"2026-11-08T02:16:47+00:00","first_seen_at":"2026-11-08T02:21:11+00:00","triaged_at":"2026-11-08T02:23:07+00:00","updated_at":"2026-11-08T02:23:07+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-08T02:23:07Z","model":"claude-haiku-5-5","output":{"fix":"- `zebrad` moves to `7.0.0` or later, per the NVD description.","reach":"network","title":"Zebra zebrad: malicious peer can stall checkpoint sync until restart","impact":"low","summary":"Zebra's zebrad node, before 7.0.0, can be stalled by a malicious peer that serves a forged block with altered authorizing data followed by a restart-triggering block. The verifier then rejects honest blocks until the node restarts, so the node stops syncing and denial of service results.","audience":"businesses","category":"package","nicknames":[],"who_cares":["zebrad","zcash","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"node stops syncing until an operator restarts it","analyst_note":"Confirm affected version range and the exact fixed version from the vendor advisory on github.com and the VulnCheck page.","how_to_check":"- Check the zebrad version with `zebrad --version`; versions below `7.0.0` are in the affected range.\n- Look for checkpoint sync stalls in node logs after peer connections.","plain_action":"","needs_analyst":true,"not_affected_if":["zebrad-7.0.0-or-later"],"who_is_affected":"Operators running zebrad nodes before 7.0.0 that accept connections from untrusted peers. The sources do not describe whether default configurations or specific deployment modes change exposure, so unknown.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000695,"input_tokens":4283,"output_tokens":534,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-123558':13A,16A '-2026':12A,15A '7.0.0':28B,75C 'allow':83C 'alter':42B,107C 'attack':100C 'author':43B,108C 'block':40B,51B,57B,105C,115C,121C 'cancel':92C 'checkpoint':7A,89C 'commit':99C 'contain':76C 'cve':11A,14A 'data':44B,109C 'denial':68B,78C 'fail':98C 'follow':45B 'forg':39B,104C 'honest':56B,120C 'host':20B 'leav':116C 'malici':3A,34B,85C 'node':26B,60B,64B 'packag':17B 'peer':4A,35B,86C 'plus':110C 'reject':55B,119C 'restart':10A,49B,61B,113C,123C 'restart-trigg':48B,112C 'result':71B 'rewind':95C 'self':19B 'self-host':18B 'serv':37B,102C 'servic':70B,80C 'stall':6A,31B,88C 'stop':65B 'sync':8A,66B,90C 'trigger':50B,114C 'verifi':53B,94C,118C 'vulner':81C 'zcash':21B 'zebra':1A,23B,72C 'zebrad':2A,22B,25B,73C","nicknames":[],"mitigations":[],"who_affected":"Operators running zebrad nodes before 7.0.0 that accept connections from untrusted peers. The sources do not describe whether default configurations or specific deployment modes change exposure, so unknown.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","package","selfhosted","zcash","zebrad"],"campaign_type":null,"search_a":"'-123558':13A,16A '-2026':12A,15A 'checkpoint':7A 'cve':11A,14A 'malici':3A 'peer':4A 'restart':10A 'stall':6A 'sync':8A 'zebra':1A 'zebrad':2A","search_b":"'7.0.0':28B 'alter':42B 'author':43B 'block':40B,51B,57B 'data':44B 'denial':68B 'follow':45B 'forg':39B 'honest':56B 'host':20B 'malici':34B 'node':26B,60B,64B 'packag':17B 'peer':35B 'reject':55B 'restart':49B,61B 'restart-trigg':48B 'result':71B 'self':19B 'self-host':18B 'serv':37B 'servic':70B 'stall':31B 'stop':65B 'sync':66B 'trigger':50B 'verifi':53B 'zcash':21B 'zebra':23B 'zebrad':22B,25B","search_c":"'7.0.0':75C 'allow':83C 'alter':107C 'attack':100C 'author':108C 'block':105C,115C,121C 'cancel':92C 'checkpoint':89C 'commit':99C 'contain':76C 'data':109C 'denial':78C 'fail':98C 'forg':104C 'honest':120C 'leav':116C 'malici':85C 'peer':86C 'plus':110C 'reject':119C 'restart':113C,123C 'restart-trigg':112C 'rewind':95C 'serv':102C 'servic':80C 'stall':88C 'sync':90C 'trigger':114C 'verifi':94C,118C 'vulner':81C 'zebra':72C 'zebrad':73C","first_public_at":"2026-10-22T12:14:40+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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-2026-123558","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123558","severity":null,"published_at":"2026-11-08T02:16:47+00:00","modified_at":"2026-11-08T02:16:47+00:00","first_seen_at":"2026-11-08T02:21:11+00:00","fetched_at":"2026-11-08T02:21:11+00:00","note":null}],"documents":[{"id":99267,"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-2w9f-9wx8-f5c8","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-22T12:14:40+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99268,"url":"https://www.vulncheck.com/advisories/zebra-before-7.0.0-checkpoint-sync-denial-of-service-via-cancelled-verifier-rewind","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, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}