CFNext: Use of a One-Way Hash with a Predictable Salt
CVE-2026-121450 is a high-severity use of a one-way hash with a predictable salt vulnerability in CFNext from PAICNI, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 3.1.0 as the first without the flaw, so updating CFNext to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.26% 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
- Update CFNext to 3.1.0 or a later version.
Affected products and versions
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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.7 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.5 | High | CNA (vulncheck.com) |
Official description
CFNext before 3.1.0 contains a weak cryptographic derivation vulnerability that allows subscription link holders to recover the admin password because the subscription UUID is an MD5 of the password with a fixed public salt. Attackers can brute-force the password offline without rate limiting, log into the admin panel, and read stored Trojan, Clash, Telegram and Cloudflare API secrets.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of a One-Way Hash with a Predictable Salt
The product uses a one-way cryptographic hash against an input that should not be reversible, such as a password, but the product uses a predictable salt as part of the input.
How developers prevent this class of flaw
- If a technique that requires extra computational effort can not be implemented, then for each password that is processed, generate a new random salt using a strong random number generator with unpredictable seeds. Add the salt to the plaintext password before hashing it. When storing the hash, also store the salt. Do not use the same salt for every password.
More Use of a One-Way Hash with a Predictable Salt vulnerabilities (CWE-760)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- github.com/PAICNI/CFNext
- github.com/PAICNI/CFNext/blob/1c7b3d8bed5b06a1449ea28302bb9a648f67e8e1/CFNext-%E6%98%8E%E6%96%87%E7%89%88.js#…
- github.com/PAICNI/CFNext/blob/1c7b3d8bed5b06a1449ea28302bb9a648f67e8e1/CFNext-%E6%98%8E%E6%96%87%E7%89%88.js#…
- github.com/PAICNI/CFNext/issues/57
- vulncheck.com/advisories/cfnext-before-3.1.0-admin-password-recovery-via-md5-derived-subscription-uuid
Recent Use of a One-Way Hash with a Predictable Salt vulnerabilities
- 9.8 Critical severity
- 7.6 High severity
- 7.5 High severity
- 9.1 Critical severity
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