What’s Vulnerable › Vulnerabilities

CVE-2025-65548

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-12-08 · updated 2026-10-18
• Weakness: CWE-1284

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.

Affected products

• Cashu Nutshell: before 0.18.0 — fixed in 0.18.0

How to fix

Upgrade to a fixed version: Cashu Nutshell 0.18.0. Check the vendor advisory for mitigations.

References

• https://bitcointalk.org/index.php?topic=5564329
• https://delvingbitcoin.org/t/public-disclosure-denial-of-service-using-htlc-in-cashu/2090
• https://github.com/cashubtc/nuts/blob/main/07.md
• https://github.com/cashubtc/nuts/blob/main/14.md
• https://github.com/jamesob/delving-bitcoin-archive/blob/master/archive/rendered-topics/2025-11-November/2025-11-02-public-disclosure-denial-of-service-using-htlc-in-cashu-id2090.md
• https://preimage007.github.io/
• https://bitcointalk.org/index.php?topic=5564329
• https://github.com/jamesob/delving-bitcoin-archive/blob/master/archive/rendered-topics/2025-11-November/2025-11-02-public-disclosure-denial-of-service-using-htlc-in-cashu-id2090.md

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