{"investigation":{"slug":"payy-network","entity_name":"Payy Network","trust_score":32,"severity_base":35,"score_modifier":-3.4,"confidence":0.72,"status":"published","content_type":"investigation","summary":"Payy Network is a privacy-focused Ethereum zk-rollup and wallet product. On 2026-09-24 its Ethereum bridge contract was drained of roughly $1.83-1.92M in USDC belonging to users' non-custodial deposits, and Payy paused the network and wallet. Payy initially said the cause was not a compromised key; a separate CVE for a flaw in Payy's own agg_agg circuit was published four days later, but no source reviewed here confirms that this flaw was the cause of the drain.","sections":[{"content":"Unchained reports that on 2026-09-24 at about 04:21 UTC the Payy Ethereum bridge was drained in a first batch of 1,828,589 USDC, leaving about $95,000, followed about five hours later by a second payout of 90,202 USDC, for about $1.92M in total. Other outlets cite about $1.83M. Both payouts went through the verifyRollup function, and Unchained reports they were submitted by the address that normally posts Payy's batches (0x5343...3D38), whose recent transactions were all verifyRollup calls. About 683 ETH was reportedly obtained from the first payout via UniswapX. Payy confirmed the funds were users' non-custodial deposits. Payy paused the network and wallet and said it flagged attacker addresses to law enforcement, exchanges and analytics firms.","heading":"September 2026 bridge drain","sources":[{"url":"https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","name":"Unchained: Payy rules out a compromised key in $1.92M drain","type":"news_article","credibility":2},{"url":"https://cryptobriefing.com/payy-network-halt-usdc-exploit-ethereum-rollup/","name":"Crypto Briefing: Payy halts operations after USDC exploit","type":"news_article","credibility":2}],"severity":"critical"},{"content":"Payy's initial analysis, as quoted by Unchained, found the drain was not a compromised key, social engineering or an exploit of off-chain infrastructure; it said it was checking findings with an unnamed audit firm. CVE-2026-48100 (published 2026-09-28; CVSS 4.0 score 8.7) describes a flaw in Payy's own agg_agg circuit, which did not check that the unused tail of its public messages array was zero, so a registered prover could insert an extra burn message that verifyRollup() would process, moving USDC out of the rollup contract. The record lists all versions before 1.3.0 as affected and 1.3.0 as the fix. It notes the deployment restricted verifyRollup() to an allowlisted prover. Crypto Briefing reports an earlier June 2026 zk-circuit flaw was patched in v1.3.0 'before any funds were lost'. None of the sources reviewed states which version Payy ran at the time of the drain, whether the fix was deployed before 2026-09-24, or that the CVE flaw was the cause of the drain. The advisory does not attribute the flaw to a third-party proving dependency. One secondary blog (Spendnode) reportedly describes a post-mortem blaming a Noir/Barretenberg verifier flaw; this was not verified against Payy's own publication and is not relied on. The cause should be treated as alleged and unconfirmed.","heading":"Cause and related security advisory","sources":[{"url":"https://app.opencve.io/cve/CVE-2026-48100","name":"OpenCVE: CVE-2026-48100","type":"official","credibility":1},{"url":"https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","name":"Unchained: Payy rules out a compromised key","type":"news_article","credibility":2},{"url":"https://cryptobriefing.com/payy-network-halt-usdc-exploit-ethereum-rollup/","name":"Crypto Briefing","type":"news_article","credibility":2}],"severity":"high"},{"content":"Early coverage (Unchained, Crypto Briefing) said Payy had not stated whether users would be repaid. DiarioBitcoin, in an article dated 2026-10-13 that relays reporting by Odaily as carried by KuCoin, says Payy opened a claims process: claims accepted for 30 days, eligible cases to be compensated in USDC on Ethereum, and the Payy Wallet suspended and expected to close after the claims period. The article gives no eligibility criteria, start date or total reimbursement commitment, and Payy's own announcement was not located, so this is secondhand reporting (medium-low confidence).","heading":"User compensation","sources":[{"url":"https://www.diariobitcoin.com/criptomonedas/payy-abre-reclamos-tras-el-hackeo-de-usd-18-millones-en-su-puente/","name":"DiarioBitcoin: Payy abre reclamos","type":"news_article","credibility":2},{"url":"https://cryptobriefing.com/payy-network-halt-usdc-exploit-ethereum-rollup/","name":"Crypto Briefing","type":"news_article","credibility":2}],"severity":"high"}],"timeline":[{"date":"2026-09-24","event":"Payy Ethereum bridge drained in two verifyRollup payouts (about $1.92M USDC); network and wallet paused.","source":"Unchained","source_url":"https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","date_evidence":"Thursday, Sept. 24, 2026: first batch at 4:21 UTC"},{"date":"2026-09","event":"Payy states in posts that the drain was not a compromised key or off-chain exploit and that it is checking findings with an audit firm.","source":"Unchained","source_url":"https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","date_original":"2026-09-25"},{"date":"2026-09-28","event":"CVE-2026-48100 published for the Payy agg_agg circuit soundness flaw, fixed in v1.3.0.","source":"OpenCVE","source_url":"https://app.opencve.io/cve/CVE-2026-48100","date_evidence":"Published: September 28, 2026 (MITRE: 2026-09-28T16:43:06Z"},{"date":"2026-10-13","event":"DiarioBitcoin reports Payy opened a 30-day claims process with USDC payouts.","source":"DiarioBitcoin","source_url":"https://www.diariobitcoin.com/criptomonedas/payy-abre-reclamos-tras-el-hackeo-de-usd-18-millones-en-su-puente/","date_evidence":"Article published: Tuesday, October 13, 2026."}],"sources_used":[{"url":"https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","name":"Unchained","type":"news_article","archive_url":"http://web.archive.org/web/20261020002540/https://unchainedcrypto.com/payy-rules-out-a-compromised-key-in-1-92-million-drain-of-users-deposits/","credibility":2,"archive_timestamp":"2026-10-20T00:25:40+00:00"},{"url":"https://cryptobriefing.com/payy-network-halt-usdc-exploit-ethereum-rollup/","name":"Crypto Briefing","type":"news_article","archive_url":"http://web.archive.org/web/20261019020443/https://cryptobriefing.com/payy-network-halt-usdc-exploit-ethereum-rollup/","credibility":2,"archive_timestamp":"2026-10-19T02:04:43+00:00"},{"url":"https://app.opencve.io/cve/CVE-2026-48100","name":"OpenCVE CVE-2026-48100","type":"official","archive_url":"http://web.archive.org/web/20261108130618/https://app.opencve.io/cve/CVE-2026-48100","credibility":1,"archive_timestamp":"2026-11-08T13:06:18+00:00"},{"url":"https://www.diariobitcoin.com/criptomonedas/payy-abre-reclamos-tras-el-hackeo-de-usd-18-millones-en-su-puente/","name":"DiarioBitcoin","type":"news_article","archive_url":"http://web.archive.org/web/20261013084904/https://www.diariobitcoin.com/criptomonedas/payy-abre-reclamos-tras-el-hackeo-de-usd-18-millones-en-su-puente/","credibility":2,"archive_timestamp":"2026-10-13T08:49:04+00:00"}],"source_tags":[],"addresses":[],"reviewed":true,"reviewed_by":null,"model_used":"claude-code-investigator","created_at":"2026-09-25T17:06:29.352589+00:00","updated_at":"2026-11-09T04:17:47.57923+00:00"},"source_quality":{"total":4,"tier1":0,"tier2":0,"tier3":0,"unrated":4},"follower_count":null,"content_updated_at":"2026-11-04T00:49:01.779Z","last_fact_checked_at":"2026-11-04T00:49:00.956Z","fact_check_next_allowed_at":"2026-11-11T00:49:00.956Z","update_next_allowed_at":"2026-11-11T00:25:51.525Z"}