CVE-2026-54496Network attack vector

Double-spend via unconstrained scalar multiplication base

Published Jul 17, 2026 · Updated Jul 17, 2026

Proof-verification bypass in affected Zcash node and library releases allows remote attackers to double-spend Orchard notes. The variable-base scalar multiplication gadget assigns its base as unconstrained witness advice, letting a malicious prover substitute a chosen base and satisfy the diversified-address-integrity equation with invalid note keys. Affected releases are Zebra before 5.0.0, halo2_gadgets before 0.5.0, orchard before 0.14.0, zcash_primitives before 0.28.0, and Zcash before 6.20.0; no privileges or user interaction are needed, and overall supply inflation is turnstile-bounded.

CVSS severity9.3
Critical
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Proof-verification bypass in affected Zcash node and library releases allows remote attackers to double-spend Orchard notes. The variable-base scalar multiplication gadget assigns its base as unconstrained witness advice, letting a malicious prover substitute a chosen base and satisfy the diversified-address-integrity equation with invalid note keys. Affected releases are Zebra before 5.0.0, halo2_gadgets before 0.5.0, orchard before 0.14.0, zcash_primitives before 0.28.0, and Zcash before 6.20.0; no privileges or user interaction are needed, and overall supply inflation is turnstile-bounded.

The record

CVE
CVE-2026-54496
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Zcash
Product
halo2_gadgets
Classifications
CWE-345
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zcash · halo2_gadgetsversion=< 0.5.0
Zcash · Zcashversion=< 6.20.0
Zcash · librustzcashversion=< 0.28.0
Zcash Foundation · Zebraversion=< 5.0.0
Zcash · orchardversion=< 0.14.0

Published CVSS scores

9.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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