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Findings

HSEC-2025-0002

Double Public Key Signing Function Oracle Attack on Ed25519

Published Nov 14, 2025 · corrected/updated Apr 18, 2026 · evidence confidence medium

# Double Public Key Signing Function Oracle Attack on Ed25519 The standard specification of Ed25519 message signing involves providing the algorithm with a message and private key. The function will use the private key to compute the public key and sign the message. Some libraries provide a variant of the message signing function that also takes the pre-computed public key as an input parameter. Libraries that allow arbitrary public keys as inputs without checking if the input public key corresponds to the input private key are vulnerable to the following attack. By using several public keys and messages, a malicious user with access to the signing mechanism may build up insights into the private key parameters resulting in access to the private key. This shortcoming means that an attacker could use the signing function as an Oracle, perform crypto-analysis and ultimately get at secrets. For example, an attacker who can’t access the private key but can access the signing mechanism through an API call could use several public keys and messages to gradually build up insights into private key parameters.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

HSEC-2025-0002 is a unknown public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: crypton (0.31 → 1.0.3); cryptonite (0.1, 0.10, 0.11). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: no CVSS/EPSS yet. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 14, 2025 · OpenSSF OSV / OSV Scanner

    Detected

    # Double Public Key Signing Function Oracle Attack on Ed25519 The standard specification of Ed25519 message signing involves providing the algorithm with a message and private key. The function will use the private key to compute the public key and sign the message. Some libraries provide a variant of the message signing function that also takes the pre-computed public key as an input parameter. L

  2. Apr 18, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    crypton fixed in 1.0.3

  3. Apr 18, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    crypton fixed in 1.0.3

  4. Apr 18, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    # Double Public Key Signing Function Oracle Attack on Ed25519 The standard specification of Ed25519 message signing involves providing the algorithm with a message and private key. The function will use the private key to compute the public key and sign the message. Some libraries provide a variant of the message signing function that also takes the pre-computed public key as an input parameter. L

Affected

  • Hackage crypton0.31 → 1.0.3
  • Hackage cryptonite0.1, 0.10, 0.11

Sources

References