CVE-2026-23965Network attack vector

Signature forgery via disabled default SM3 hashing

Published Jan 22, 2026 · Updated Jan 22, 2026

Improper SM2 signature verification in JuneAndGreen sm-crypto before 0.4.0 allows remote attackers to forge signatures for arbitrary public keys. The doVerifySignature function leaves the hash option disabled by default, treating attacker-controlled message bytes as the SM2 digest instead of hashing them with SM3. The default path requires no privileges or user interaction and lets forged signatures pass integrity checks; redundant message formats can retain a chosen prefix.

CVSS severity7.5
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper SM2 signature verification in JuneAndGreen sm-crypto before 0.4.0 allows remote attackers to forge signatures for arbitrary public keys. The doVerifySignature function leaves the hash option disabled by default, treating attacker-controlled message bytes as the SM2 digest instead of hashing them with SM3. The default path requires no privileges or user interaction and lets forged signatures pass integrity checks; redundant message formats can retain a chosen prefix.

The record

CVE
CVE-2026-23965
Published
Jan 22, 2026
Updated
Jan 22, 2026
Vendor
JuneAndGreen
Product
sm-crypto
Classifications
CWE-347
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 22, 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=< 0.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JuneAndGreen · sm-cryptoversion=< 0.4.0

Published CVSS scores

7.5GitHubCVSS: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.

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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-347Improper Verification of Cryptographic Signature

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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