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CVE-2026-107245NVD status: Awaiting Analysis

VOS: Stack-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-107245 is a high-severity stack-based buffer overflow vulnerability in VOS from Versa, 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. The record lists versions July 2, 2026, 23.1.2 as the first without the flaw, so updating VOS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.38% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update VOS to July 2, 2026 or 23.1.2, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
VersaVOS21.1.1 through 21.2.3; 22.1.2 up to, but not including, July 2, 2026; 22.1.3 up to, but not including, July 2, 2026; 22.1.4 up to, but not including, July 2, 2026; 23.1.2 up to, but not including, 23.1.2July 2, 2026, 23.1.2

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
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).

Official description

Versa has confirmed a buffer overflow vulnerability in the IPsec implementation on VOS, aka Versa FlexVNF. Buffer Overflow Vulnerability Description When a maliciously crafted IKE Auth packet is sent to VOS, the vsmd process crashes, thereby resulting in a Denial of Service. An attacker can create a Denial-of-Service attack on the VOS appliances by crafting a malicious IKE Auth packet and sending it to the WAN interfaces on the VOS. During the IKE Authentication phase, if the IKE SA negotiation fails, and the size of the Remote ID is larger than the buffer size used to process the Remote ID, it will result in a crash of the vsmd process on the VOS appliance. What is impacted? VOS nodes configured with IPsec VPN profiles of type controller-staging-sdwan or remote-access-server using a WAN interface as the IPsec endpoint are vulnerable. (IPsec profiles configured with an overlay interface as the IPsec endpoint are not affected.) This configuration typically applies to all Controllers, Hub Controllers, and SSE Gateways. Additionally, site-to-site VPN profiles configured without a peer IP address, hostname, or FQDN are also vulnerable. What is not impacted? The VOS nodes listed above are not vulnerable if they are not accessible from the Internet.

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.

More Stack-based Buffer Overflow vulnerabilities (CWE-121)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in VOS

All VOS vulnerabilities

Recent Stack-based Buffer Overflow vulnerabilities

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