CVE-2026-48100Payy: agg_agg trailing message slots are unconstrained and allow forged burn messages
- 8.7HighCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
Payy is an Ethereum L2 zk-rollup for privacy preserving and regulatory compliant transactions. Prior to version 1.3.0, agg_agg forwards the compacted message stream from its inner proofs into a public messages: [Field; 1000] array, but it never checks that the unused tail of the outer array is zero. A registered prover can build a valid agg_final proof for an approved rollup block while inserting an extra burn message after the real messages. RollupV1.verifyRollup() then parses that public input as a normal burn and transfers USDC from the rollup contract to the attacker. This is a severe circuit soundness failure: the proof system accepts a public statement whose messages array is not fully derived from the verified inner proofs. On the current deployment, verifyRollup() is restricted to the existing allowlisted prover, so a fresh public caller cannot submit the invalid proof directly. That gate limits who can reach L1 today; it does not make the circuit statement sound. The issue becomes permissionless under the prover model described in the Payy whitepaper. Section 3.3.2 states: "To join as a prover, the prover is required to submit a small stake", and Section 3.3.1 states that if a prover fails to submit, "other nodes can submit the block proof instead." In that model, an attacker only needs to become a registered prover and use public validator approval data for an already approved block. This issue has been patched in version 1.3.0.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/polybase/payy/security/advisories/GHSA-fhxc-63vg-9gwr (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 4 months later
· 4 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |
| NVDNVD · Deferred | 4.0 | High8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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 |
- EPSS (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.
Affected products
References
References1
- https://github.com/polybase/payy/security/advisories/GHSA-fhxc-63vg-9gwr (opens in a new tab)x_refsource_CONFIRMexploit
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-88359 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-48100)Record last updated .