CVE-2021-3990Network attack vector

LDAP account compromise via timestamp-derived passwords

Published Dec 1, 2021 · Updated Aug 3, 2024

Predictable LDAP password generation in ShowDoc before 2.9.13 allows remote attackers to compromise automatically created user accounts. The LDAP registration paths derive each new local password from the LDAP username and current Unix timestamp instead of cryptographically random data. LDAP integration must create a previously unseen directory user; knowledge of the username and narrow creation time then permits access through local authentication.

CVSS severity6.5
Medium
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Predictable LDAP password generation in ShowDoc before 2.9.13 allows remote attackers to compromise automatically created user accounts. The LDAP registration paths derive each new local password from the LDAP username and current Unix timestamp instead of cryptographically random data. LDAP integration must create a previously unseen directory user; knowledge of the username and narrow creation time then permits access through local authentication.

The record

CVE
CVE-2021-3990
Published
Dec 1, 2021
Updated
Aug 3, 2024
Vendor
ShowDoc
Product
ShowDoc
Classifications
CWE-338, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 <2.9.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ShowDoc · ShowDocversion=unspecified <2.9.13

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
6.5huntr.devCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
4.3NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:N

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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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