CVE-2021-45841Public exploitNetwork attack vector

Unauthenticated guest login via self-signed session cookies

Published Apr 25, 2022 · Updated Aug 4, 2024

Improper authentication in TerraMaster TOS 4.2.15-2107141517 allows remote attackers to forge session cookies and log in. The login path accepts a kod_token computed as MD5 over part of the device MAC address and the selected user's password hash, including an empty guest hash. Exploitation requires those values for a normal account, while the disabled-by-default guest account permits unauthenticated guest access when enabled.

CVSS severity8.1
High
EPSS probability8.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in TerraMaster TOS 4.2.15-2107141517 allows remote attackers to forge session cookies and log in. The login path accepts a kod_token computed as MD5 over part of the device MAC address and the selected user's password hash, including an empty guest hash. Exploitation requires those values for a normal account, while the disabled-by-default guest account permits unauthenticated guest access when enabled.

The record

CVE
CVE-2021-45841
Published
Apr 25, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-798, CWE-287, T1550.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
CWE-287Improper Authentication
T1550.004Use Alternate Authentication Material: Web Session Cookie

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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