Hy511 Firmware: Reliance on Cookies without Validation and Integrity Checking
CVE-2025-65212 is a critical-severity reliance on cookies without validation and integrity checking vulnerability in Hy511 Firmware from Njhyst, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2.1 as the first without the flaw, so updating Hy511 Firmware to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 5.36% chance of exploitation within 30 days, which is in the top 7.23% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Hy511 Firmware to 2.1 or a later version.
- 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 |
|---|---|---|---|
| Njhyst | Hy511 Firmware | before 2.1 | 2.1 |
Version data comes from NVD's product matching. 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
- 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:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
An issue was discovered in NJHYST HY511 POE core before 2.1 and plugins before 0.1. The vulnerability stems from the device's insufficient cookie verification, allowing an attacker to directly request the configuration file address and download the core configuration file without logging into the device management backend. By reading the corresponding username and self-decrypted MD5 password in the core configuration file, the attacker can directly log in to the backend, thereby bypassing the front-end backend login page.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reliance on Cookies without Validation and Integrity Checking
The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.
How developers prevent this class of flaw
- Avoid using cookie data for a security-related decision.
- Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.
- Add integrity checks to detect tampering.
More Reliance on Cookies without Validation and Integrity Checking vulnerabilities (CWE-565)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- gist.github.com/a2148001284/bcdda75fc8718454f16a7b9259463719Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/a2148001284/test1/blob/main/%E6%9C%AA%E6%8E%88%E6%9D%83%E8%AE%BF%E9%97%AE%E5%90%8E%E5%8F%B0%E6%BC%…Exploit, Third Party Advisory
Recent Reliance on Cookies without Validation and Integrity Checking vulnerabilities
- 9.8 Critical severity
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
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