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Fencer Intel
critical 9.8

CVE-2020-27539 json

Heap overflow with full parsing of HTTP respose in Rostelecom CS-C2SHW 5.0.082.1.

published 5y ago modified 4mo ago also EUVD-2020-20048

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

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.

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Exploit prediction

1.28% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • dil4rd.medium.com https://dil4rd.medium.com/groundhog-day-in-iot-valley-or-5-cves-in-1-camera-7dc1d2864707 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.