CVE-2021-37551Network attack vector

Offline password cracking via weak SHA-256 hashing

Published Aug 6, 2021 · Updated Aug 4, 2024

Weak password hashing in JetBrains YouTrack before 2021.2.16363 allows remote attackers to crack system user passwords after obtaining password hashes. The system-user password storage implementation relies on fast SHA-256 hashing, which provides insufficient computational cost against offline guessing. Exploitation requires prior access to the stored password hashes; the record does not describe a direct request that bypasses authentication or alters service availability.

CVSS severity5.3
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak password hashing in JetBrains YouTrack before 2021.2.16363 allows remote attackers to crack system user passwords after obtaining password hashes. The system-user password storage implementation relies on fast SHA-256 hashing, which provides insufficient computational cost against offline guessing. Exploitation requires prior access to the stored password hashes; the record does not describe a direct request that bypasses authentication or alters service availability.

The record

CVE
CVE-2021-37551
Published
Aug 6, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-916, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 6, 2021CVE 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

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-916Use of Password Hash With Insufficient Computational Effort
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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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