CVE-2023-39910

Name: CVE-2023-39910
Creator: NVD / NIST
Published: 2023-08-09T03:15:44.867+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.31%

Last modified Jun 17, 2026

CVE-2023-39910 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. The cryptocurrency wallet entropy seeding mechanism used in Libbitcoin Explorer 3.0.0 through 3.6.0 is weak, aka the Milk Sad issue. The use of an mt19937 Mersenne Twister PRNG restricts the internal entropy to 32 bits regardless of settings. EPSS estimates a 1.31% chance of exploitation in the next 30 days.

Description

The cryptocurrency wallet entropy seeding mechanism used in Libbitcoin Explorer 3.0.0 through 3.6.0 is weak, aka the Milk Sad issue. The use of an mt19937 Mersenne Twister PRNG restricts the internal entropy to 32 bits regardless of settings. This allows remote attackers to recover any wallet private keys generated from "bx seed" entropy output and steal funds. (Affected users need to move funds to a secure new cryptocurrency wallet.) NOTE: the vendor's position is that there was sufficient documentation advising against "bx seed" but others disagree. NOTE: this was exploited in the wild in June and July 2023.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.31%

67.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-338

Affected Software

Vendor	Product	Versions
Libbitcoin	Libbitcoin Explorer	>= 3.0.0, <= 3.6.0

References

https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/commands/seed.cpp#L44Third Party Advisory
https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/utility.cpp#L78Third Party Advisory
https://github.com/libbitcoin/libbitcoin-explorer/wiki/CVE-2023-39910
https://github.com/libbitcoin/libbitcoin-system/blob/a1b777fc51d9c04e0c7a1dec5cc746b82a6afe64/src/crypto/pseudo_random.cpp#L66C12-L78Third Party Advisory
https://milksad.info/disclosure.htmlThird Party Advisory
https://news.ycombinator.com/item?id=37054862Third Party Advisory
https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/commands/seed.cpp#L44Third Party Advisory
https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/utility.cpp#L78Third Party Advisory
https://github.com/libbitcoin/libbitcoin-explorer/wiki/CVE-2023-39910
https://github.com/libbitcoin/libbitcoin-system/blob/a1b777fc51d9c04e0c7a1dec5cc746b82a6afe64/src/crypto/pseudo_random.cpp#L66C12-L78Third Party Advisory
https://milksad.info/disclosure.htmlThird Party Advisory
https://news.ycombinator.com/item?id=37054862Third Party Advisory

Timeline

Published: Aug 9, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-39910?

How severe is CVE-2023-39910?

CVE-2023-39910 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.31% probability of exploitation in the next 30 days.

How do I fix CVE-2023-39910?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-39910?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST