CVE-2021-3555Public exploit

Pre-auth code execution via unchecked digest parameters

Published May 31, 2022 · Updated Sep 17, 2024

Stack-based buffer overflow in the RTSP server of Eufy Indoor Cam 2K 2.0.9.3 and earlier allows remote attackers to execute code. The zx_rtsp_auth_parse_section function copies digest-authentication parameters into fixed stack buffers without checking their boundaries, enabling control of the stack pointer and a jump to shellcode on the heap. Exploitation requires local-network access and the optional RTSP server's digest authentication, which is disabled by default.

CVSS severity7.6
High
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in the RTSP server of Eufy Indoor Cam 2K 2.0.9.3 and earlier allows remote attackers to execute code. The zx_rtsp_auth_parse_section function copies digest-authentication parameters into fixed stack buffers without checking their boundaries, enabling control of the stack pointer and a jump to shellcode on the heap. Exploitation requires local-network access and the optional RTSP server's digest authentication, which is disabled by default.

The record

CVE
CVE-2021-3555
Published
May 31, 2022
Updated
Sep 17, 2024
Vendor
Eufy
Product
Eufy Indoor Cam 2K
Classifications
CWE-120, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 31, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=2.0.9.3

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Eufy · Eufy Indoor Cam 2Kversion=unspecified <=2.0.9.3

Published CVSS scores

7.6BitdefenderCVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1210Exploitation of Remote Services

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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