CVE-2023-24533

Incorrect P-256 results via missing scalar reduction

Published Mar 8, 2023 · Updated Feb 28, 2025

Incorrect P-256 scalar multiplication in Filippo Valsorda nistec before 0.0.2 allows attackers to obtain incorrect curve results. The P-256 assembly path uses incomplete addition formulas, and its scalar loops checked only input length instead of reducing unreduced scalars modulo the group order. Triggering requires a caller to supply certain unreduced P-256 scalars to ScalarBaseMult or ScalarMult; no attackable protocols are known, so the demonstrated consequence is limited to incorrect computation.

CVSS severity7.5
High
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect P-256 scalar multiplication in Filippo Valsorda nistec before 0.0.2 allows attackers to obtain incorrect curve results. The P-256 assembly path uses incomplete addition formulas, and its scalar loops checked only input length instead of reducing unreduced scalars modulo the group order. Triggering requires a caller to supply certain unreduced P-256 scalars to ScalarBaseMult or ScalarMult; no attackable protocols are known, so the demonstrated consequence is limited to incorrect computation.

The record

CVE
CVE-2023-24533
Published
Mar 8, 2023
Updated
Feb 28, 2025
Vendor
Filippo Valsorda
Product
nistec
Classifications
CWE-682
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Mar 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 28, 2025Record 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 <0.0.2

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Filippo Valsorda · nistecversion=0 <0.0.2

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-682Incorrect Calculation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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