CVE-2026-23965VulnerabilityPublished 22 Jan 2026

CVE-2026-23965: JuneAndGreen sm-crypto · Improper Verification of Cryptographic Signature

Affects JuneAndGreen sm-cryptoSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 0.4.0 soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.4.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade JuneAndGreen sm-crypto to 0.4.0.

Affected software

Product	Affected	Fixed in
JuneAndGreensm-crypto	Affected <0.4.0	Fixed in 0.4.0
npmsm-crypto`pkg:npm/sm-crypto`Other threats	Affected <0.4.0	Fixed in 0.4.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately audit their software and systems to identify any usage of the sm-crypto library, especially versions prior to 0.4.0. They must upgrade all instances of sm-crypto to version 0.4.0 or later, where the signature verification flaw is patched. For custom or embedded implementations of SM2 signature verification, a thorough code review and testing should be conducted to ensure compliance with correct cryptographic verification standards. Organizations should also consider implementing additional cryptographic validation layers or fallback mechanisms to detect forged signatures. Monitoring network traffic and application logs for anomalous signature verification failures or suspicious message patterns can help detect exploitation attempts. Where feasible, limiting exposure of services using SM2 signatures to trusted networks and enforcing strict access controls can reduce attack surface. Finally, organizations should engage with their software vendors and supply chain partners to confirm that patched versions are deployed and to raise awareness about this vulnerability.

Description

CVE-2026-23965 is a high-severity vulnerability in the sm-crypto JavaScript library implementing Chinese cryptographic algorithms SM2, SM3, and SM4. The flaw lies in the SM2 signature verification logic prior to version 0.4.0, allowing attackers to forge valid signatures for arbitrary public keys without authentication or user interaction. This signature forgery can be exploited when the message space has sufficient redundancy, enabling attackers to craft messages with fixed prefixes that satisfy verification requirements. The vulnerability impacts the integrity of cryptographic operations, potentially allowing unauthorized actions or data tampering. No known exploits are currently reported in the wild. The issue is patched in sm-crypto version 0.4.0.

Impact

For European organizations, the vulnerability poses a significant risk to systems that utilize the sm-crypto library or SM2 cryptographic signatures, particularly in environments where Chinese cryptographic standards are adopted or integrated. The forgery of digital signatures can lead to unauthorized access, fraudulent transactions, data tampering, and bypass of authentication or authorization controls. This undermines the integrity of communications, software updates, or document signing processes relying on SM2 signatures. Organizations in sectors such as finance, telecommunications, critical infrastructure, and government that engage with Chinese technology providers or standards may be particularly vulnerable. The compromise of signature integrity can also affect supply chain security and trust in digital certificates. Given the network-exploitable nature and no requirement for privileges or user interaction, the threat can be exploited remotely and stealthily, increasing the risk of widespread impact if the vulnerable library is used in exposed services or applications.

CWE-347Improper Verification of Cryptographic Signature (opens in a new tab)
Base weaknessOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
Padding Oracle Crypto Attack (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jan 2026, 08:50 UTC

WeaknessesCWE-347

Technical details

References

Community reviews

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