# CVE-2026-62646: Siemens Reyrolle 7SR5 weak session identifier generation

Source: https://junglewise.ai/threats/cve-2026-62646-siemens-reyrolle-7sr5-weak-session-identifier-generation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-62646 · Severity: high · CVSS 7.4 · Published 2026-09-08

Siemens Reyrolle 7SR5 is a protection and automation device used in electrical substations to control critical infrastructure. A flaw in how the device generates session identifiers allows attackers to predict valid login tokens and bypass authentication without credentials, potentially granting unauthorized remote access to critical power system controls.

Technologies: [Siemens Reyrolle 7SR5](https://junglewise.ai/threats/technologies/reyrolle-7sr5). Vendors: [Siemens](https://junglewise.ai/threats/vendors/siemens).

## Quick answers

**Is CVE-2026-62646 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-62646 being exploited in the wild.

**How severe is CVE-2026-62646?** High severity, with a CVSS score of 7.4, published 8 September 2026.

**Which products and versions are affected?** Siemens Reyrolle 7SR5 All versions < V2.70.

**Is there a fix for CVE-2026-62646?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-62646 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-62646?** Check whether you run Siemens Reyrolle 7SR5 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability (CVE-2026-62646) stems from insufficient entropy in the session identifier generation algorithm (CWE-331). An unauthenticated remote attacker can predict or brute-force session identifiers within a feasible number of attempts due to the low randomness of the token generation. This enables authentication bypass and unauthorized device access. No user interaction is required. Siemens has released a patch available in version 2.70 and later.

## Affected products

- Siemens Reyrolle 7SR5 All versions < V2.70

## Timeline

- 2026-09-08: disclosed

## References

- [https://cert-portal.siemens.com/productcert/html/ssa-142885.html](https://cert-portal.siemens.com/productcert/html/ssa-142885.html)

## Related threats

- [Siemens Reyrolle 7SR5 unsigned code execution in maintenance mode](https://junglewise.ai/threats/cve-2026-62654-siemens-reyrolle-7sr5-unsigned-code-execution-in-maintenance-mode)
- [Siemens Reyrolle 7SR5 memory corruption in firmware-update protocol](https://junglewise.ai/threats/cve-2026-62653-siemens-reyrolle-7sr5-memory-corruption-in-firmware-update)
- [Siemens Reyrolle 7SR5 unstripped debug symbols in firmware](https://junglewise.ai/threats/cve-2026-62652-siemens-reyrolle-7sr5-unstripped-debug-symbols-in-firmware)
- [Siemens Reyrolle 7SR5 privilege escalation via RBAC bypass](https://junglewise.ai/threats/cve-2026-62650-siemens-reyrolle-7sr5-privilege-escalation-via-rbac-bypass)
- [Siemens Reyrolle 7SR5 denial-of-service via resource exhaustion](https://junglewise.ai/threats/cve-2026-62649-siemens-reyrolle-7sr5-denial-of-service-via-resource-exhaustion)