Actualizer: Use of Weak Hash
CVE-2025-47276 is a high-severity use of weak hash vulnerability in Actualizer from ChewKeanHo, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Actualizer versions: < 1.2.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Actualizer you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| ChewKeanHo | Actualizer | < 1.2.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CNA (github.com).
Official description
Actualizer is a single shell script solution to allow developers and embedded engineers to create Debian operating systems (OS). Prior to version 1.2.0, Actualizer uses OpenSSL's "-passwd" function, which uses SHA512 instead of a more suitable password hasher like Yescript/Argon2i. All Actualizer users building a full Debian Operating System are affected. Users should upgrade to version 1.2.0 of Actualizer. Existing OS deployment requires manual password changes against the alpha and root accounts. The change will deploy's Debian's yescript overriding the older SHA512 hash created by OpenSSL. As a workaround, users need to reset both `root` and "Alpha" users' passwords.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Weak Hash
The product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use of Weak Hash vulnerabilities
- 9.8 Critical severity
- 9.3 Critical severity
- 8.7 High severity
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