PT-2025-49588 · Altcha · Altcha

Published 2025-12-08 · Updated 2025-12-08 · CVE-2025-65849

Positive Technologies (AI Summary)

CVSS v3.1

9.1

Critical

Base vector

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

Name of the Vulnerable Software and Affected Versions Altcha versions 0.8.0 and later

Description A flaw exists in the Altcha Proof-of-Work obfuscation mode that allows a remote attacker to recover the Proof-of-Work nonce in constant time through mathematical deduction. This is due to a cryptanalytic break in the obfuscation method.

Recommendations Update to a newer version of Altcha that addresses this issue. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Use of a Broken Cryptographic Algorithm

Weakness Enumeration

CWE-327

Related Identifiers

CVE-2025-65849

GHSA-MPMC-QCHH-R9Q8

Affected Products

Altcha

References · 8

• https://osv.dev/vulnerability/CVE-2025-65849 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-65849 · Security Note
• https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194 · Note
• https://twitter.com/CVEnew/status/1998103559728934938 · Twitter Post
• https://t.me/CVEtracker/39155 · Telegram Post
• https://twitter.com/VulmonFeeds/status/1998154686260445299 · Twitter Post
• https://github.com/eternal-flame-AD/altcha-deobfs · Note
• https://altcha.org/docs/v2/obfuscation · Note