VulnerabilityPublished 8 Dec 2025Updated 11 Dec 2025

CVE-2025-65548: nuts · Improper Validation of Specified Quantity in Input

Affects nutsSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical : upgrade to 0.18.0 as a priority.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

9.1Critical

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.18.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 8 Dec 2025
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 26 Oct 2026.

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 or the CVSS exploit maturity 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 cashubtc/nuts to 0.18.0.

Affected software

Product	Affected	Fixed in
GitHubcashubtc/nuts`pkg:github/cashubtc/nuts`Other threats	Affected <0.18.0	Fixed in 0.18.0

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

AI-suggested

The primary mitigation is to upgrade nutshell to version 0.18.0 or later, where proper validation of preimage sizes is enforced. Until an upgrade is possible, organizations should implement input validation at the application or network layer to restrict the size of preimage data accepted by the mint. Rate limiting and anomaly detection mechanisms should be deployed to identify and block abnormal token spend requests with unusually large preimages. Monitoring disk usage and database growth closely can provide early warning signs of exploitation attempts. Additionally, segregating the mint’s database storage on dedicated volumes with quota management can limit the impact of resource exhaustion. Organizations should also review and harden their incident response plans to address potential denial-of-service scenarios related to this vulnerability. Engaging with the nutshell vendor or community for patches and security advisories is recommended to stay updated on fixes and best practices.

Description

NUT-14 allows cashu tokens to be created with a preimage hash. However, nutshell (cashubtc/nuts) before 0.18.0 do not validate the size of preimage when the token is spent. The preimage is stored by the mint and attacker can exploit this vulnerability to fill the mint's db nd disk with arbitrary data.

Impact

For European organizations, especially those involved in cryptocurrency services, fintech, or digital payment systems utilizing nutshell for cashu token management, this vulnerability poses a significant risk of denial-of-service attacks. An attacker could remotely flood the mint’s storage with large preimage data, causing database bloat and disk exhaustion, which may lead to system crashes, service unavailability, and potential data corruption. This disruption could affect transaction processing, customer trust, and regulatory compliance, particularly under stringent EU data protection and operational resilience requirements. The inability to process legitimate token spends could also impact financial operations and liquidity. Additionally, recovery from such an attack might require costly database maintenance or hardware upgrades. Given the critical severity and ease of exploitation, the threat could be leveraged by cybercriminals or hacktivists targeting European crypto infrastructure to cause operational disruptions.

CWE-1284Improper Validation of Specified Quantity in Input (opens in a new tab)
Base weakness
The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Dec 2025, 04:43 UTC

WeaknessesCWE-1284

Technical details

References

Community reviews

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