PatchTheCVECVE-2020-27539: Heap overflow with full parsing of HTTP respose in Rostelecom CS-C2SHW 5.0.082.1
CVE-2020-27539 is a critical-severity flaw (CVSS 9.8) affecting cs-c2shw firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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). In default configuration camera parses responses only from HTTPS URLs from config file, so vulnerable code is unreachable and one more bug required to reach it.
Why this priority
- Critical severity
- Public exploit reference
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.3% (top 30%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2021-01-26 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2020-27539?
cs-c2shw firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2020-27539 being exploited?
CVE-2020-27539 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2020-27539 affect?
CVE-2020-27539 affects cs-c2shw firmware. Severity is critical (CVSS 9.8). 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). In default configuration camera parses re
How urgent is CVE-2020-27539?
Priority 62/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2020-27542 MEDIUM 6.8 MITIGATE Rostelecom CS-C2SHW 5.0.082.1 is affected by: Bash command injection
- CVE-2020-27541 HIGH 7.5 MITIGATE Denial of Service vulnerability in Rostelecom CS-C2SHW 5.0.082.1
- CVE-2020-27540 CRITICAL 9.8 MITIGATE Bash injection vulnerability and bypass of signature verification in Rostelecom CS-C2SHW 5.0.082.1