Vulnerability in Ledger Flex
CVE-2025-15645
Ledger Nano X, Flex, and Stax devices contain a denial of service vulnerability in the MCU firmware update process due to missing validation of the reset_handler parameter during firmware flashing. An attacker can provide a crafted reset_handler address pointing to invalid memory or attacker-controlled code to cause the device to enter an unrecoverable fault state during boot, resulting in permanent loss of operability.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.002 (10.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Ledger Flex — versions 0
- Ledger Nano X — versions 0
- Ledger Stax — versions 0
Weakness classification (CWE)
References
- www.ledger.com/security-bulletin (vendor-advisory)
- www.vulncheck.com/advisories/ledger-nano-x-flex-stax-mcu-firmware-update-denial… (third-party-advisory)
- donjon.ledger.com/lsb/021/ (vendor-advisory)
Frequently asked questions
- What is CVE-2025-15645?
- CVE-2025-15645 is a medium-severity vulnerability in Ledger Flex, classified under Improper Validation of Specified Quantity in Input. CVSS score: 4.6/10. Published 2026-05-19.
- How severe is CVE-2025-15645?
- Medium severity. CVSS v3 base score is 4.6 out of 10.