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 t
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | cashu | < 0.18.0 | 0.18.0 |
References
- https://delvingbitcoin.org/t/public-disclosure-denial-of-service-using-htlc-in-cashu/2090
- https://preimage007.github.io/
- https://bitcointalk.org/index.php?topic=5564329
- 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
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
-- Platform
- Python (PyPI)
- Package
cashu- Disclosed
- 08.12.2025
- Updated
- 11.10.2026 12:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2025-89 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: cashu
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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