700 Series: Reachable Assertion
CVE-2026-39453 is a high-severity reachable assertion vulnerability in 700 Series from Red Lion Controls, with a CVSS 3.1 base score of 8.3 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 versions Firmware Versions 3.11.0, Bootloader Versions 2.0.6.1 as the first without the flaw, so updating 700 Series to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% 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 700 Series to Firmware Versions 3.11.0 or Bootloader Versions 2.0.6.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Lion Controls | 700 Series | before Firmware Versions 3.11.0; before Bootloader Versions 2.0.6.1 | Firmware Versions 3.11.0, Bootloader Versions 2.0.6.1 |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data 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:L/UI:N/S:U/C:L/I:H/A:H. Scored by CNA (hq.dhs.gov).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.5 | High | CNA (hq.dhs.gov) |
| CVSS 3.1 | 8.3 | High | CNA (hq.dhs.gov) |
Official description
Navigating to a certain URL on the switch’s web server causes the switch to reboot. This can be automated using a tool like curl to create DoS conditions where the switch constantly reboots.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reachable Assertion
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
How developers prevent this class of flaw
- If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
- Consider changing the assertion to some other less fatal error. This might not be easy to implement, since other code may be needed to handle the error.
- Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in 700 Series
- 8.1 High severity
- 8.1 High severity
- 7.1 High severity
- 7.5 High severity
Recent Reachable Assertion vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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