Critical Vulnerability: CVE-2020-27539 — company — cs-c2shw_firmware, cs-c2shw

CVE-2020-27539 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. Heap overflow with full parsing of HTTP respose in Rostelecom CS-C2SHW 5.0.082.1. AgentUpdater service has a self-written HTTP parser and builder. HTTP parser has a heap buffer overflow (OOB write). I

Check whether your environment runs cs-c2shw_firmware, cs-c2shw. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.

Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2020-27539. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.