MPVPN: Stack-based Buffer Overflow
CVE-2026-90823 is a critical-severity stack-based buffer overflow vulnerability in MPVPN from FatPipe Networks, 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. Affected MPVPN versions: 10.1.2r60p100. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of MPVPN you run against the affected versions below, and install the vendor's latest release.
- 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 |
|---|---|---|---|
| FatPipe Networks | MPVPN | 10.1.2r60p100 | Not stated |
| FatPipe Networks | WARP | 10.1.2r60p100 | Not stated |
| FatPipe Networks | IPVPN | 10.1.2r60p100 | 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
- 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 CNA (securifera.com).
Official description
FatPipe MPVPN, WARP, and IPVPN appliances running the end-of-life firmware version 10.1.2r60p100 contain a stack-based buffer overflow in /usr/sbin/auth_user_pass. An unauthenticated remote attacker with access to the affected management interface can submit a crafted authentication request that reaches an unchecked copy into a fixed-size stack buffer, potentially allowing arbitrary code execution as root. The affected management interface is disabled by default and must be affirmatively enabled by the customer before the endpoint becomes reachable. FatPipe recommends restricting management access to trusted administrative networks and using WAN access control lists to limit access to trusted sources. Customers running the affected end-of-life firmware can contact FatPipe Support for help confirming their firmware version and upgrading to a current supported release at https://www.fatpipeinc.com/support/support, [email protected], or +1 800-724-8521 (option 3).
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in MPVPN
- 9.8 Critical severity
Recent Stack-based Buffer Overflow vulnerabilities
- 9.6 Critical severity
- 7.8 High severity
- 7.2 High severity
- 7.7 High severity
- 8.8 High severity
- 7.2 High severity
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