{"id":"CVE-2026-62337","title":"SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements","summary":"SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. `EcPointLoader::multi_scalar_multiplication` places a `Value::Assigned(_)` base pai…","severity":"medium","cvss":6.9,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","cvssSource":"cna","cwe":["CWE-20"],"vendor":"axiom-crypto","product":"snark-verifier","affected":["snark-verifier < 0.2.5"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-11-02T14:58:24.604760Z"},"published":"2026-10-30","updated":"2026-11-02","sourceUpdated":"2026-11-02T14:58:37.998Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-62337","references":[{"url":"https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-x26x-7f4v-cqx7","label":"https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-x26x-7f4v-cqx7"},{"url":"https://github.com/axiom-crypto/halo2-lib/commit/f53be0939e2accf0dd7672b1a4abe80af73dadf3","label":"https://github.com/axiom-crypto/halo2-lib/commit/f53be0939e2accf0dd7672b1a4abe80af73dadf3"},{"url":"https://github.com/axiom-crypto/snark-verifier/commit/bbfcc721d714bea0d44a27c8fc6c4736e73ca853","label":"https://github.com/axiom-crypto/snark-verifier/commit/bbfcc721d714bea0d44a27c8fc6c4736e73ca853"},{"url":"https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5","label":"https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5"}],"tags":["cve.org"],"epss":0.00301,"epssPercentile":0.2301,"ingestedAt":"2026-11-05T19:30:42.675Z","slug":"CVE-2026-62337","body":"## Overview\n\nSNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. `EcPointLoader::multi_scalar_multiplication` places a `Value::Assigned(_)` base paired with `Value::Constant(ONE)` into its unscaled variable-base list and passes it directly to `sum_with_const`. The default shim delegates to halo2-lib `EccChip::sum`, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as `(0, 0)` can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.\n\n## Affected\n\n- `snark-verifier < 0.2.5`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":38,"depthScoreParts":{"impact":38,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}