Reyrolle 7SR5: Insufficient Entropy
CVE-2026-62646 is a high-severity insufficient entropy vulnerability in Reyrolle 7SR5 from Siemens, with a CVSS 3.1 base score of 7.4 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 V2.70 as the first without the flaw, so updating Reyrolle 7SR5 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.51% 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 Reyrolle 7SR5 to V2.70 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 |
|---|---|---|---|
| Siemens | Reyrolle 7SR5 | before V2.70 | V2.70 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.1 | Critical | CNA (siemens.com) |
| CVSS 3.1 | 7.4 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in Reyrolle 7SR5 (All versions < V2.70). A session identifier is generated using an algorithm with insufficient randomness, resulting in a token with low entropy that can be predicted or brute-forced within a feasible number of attempts. This could allow an unauthenticated remote attacker to derive valid session identifiers and bypass authentication.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Entropy
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.
How developers prevent this class of flaw
- Determine the necessary entropy to adequately provide for randomness and predictability. This can be achieved by increasing the number of bits of objects such as keys and seeds.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Reyrolle 7SR5
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.4 High severity
- 9.8 Critical severity
- 7.5 High severity
Recent Insufficient Entropy vulnerabilities
- 9.0 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
- 7.3 High severity
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