VOS: Generation of Predictable Numbers or Identifiers
CVE-2026-107242 is a critical-severity generation of predictable numbers or identifiers vulnerability in VOS from Versa, with a CVSS 3.1 base score of 9.1 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, Aug 3, 2026 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 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update VOS to July 2, 2026 or Aug 3, 2026, whichever matches your release line, 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 |
|---|---|---|---|
| Versa | VOS | 21.1.1 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, Aug 3, 2026 | July 2, 2026, Aug 3, 2026 |
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
- 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:H/I:N/A:H. Scored by CISA (ADP).
Official description
The Node.js web service on VOS (previously Versa FlexVNF) is used for URL-based Zero Touch Provisioning (ZTP) of the VOS appliance and is not required after provisioning is complete. This service generates session identifiers using UUID version 1 (UUIDv1), which is derived from the system’s date and time and its MAC address. As a result, successive identifiers differ only slightly and can be predicted. An attacker who can predict a user’s session ID could hijack that user’s session. Versa’s security hardening guide for Hubs, Branches, and Controllers recommends disabling the Node.js web service after the initial provisioning of the VOS device. This vulnerability is not exploitable on VOS devices where the Node.js web service has been disabled.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Generation of Predictable Numbers or Identifiers
The product uses a scheme that generates numbers or identifiers that are more predictable than required.
More Generation of Predictable Numbers or Identifiers vulnerabilities (CWE-340)
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
Other vulnerabilities in VOS
- 7.5 High severity
- 7.6 High severity
- 7.6 High severity
- 7.6 High severity
- 7.6 High severity
Recent Generation of Predictable Numbers or Identifiers vulnerabilities
- 4.3 Medium severity
- 7.7 High severity
- 8.8 High severity
- 7.5 High severity
- 9.1 Critical severity
- 8.2 High severity
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