CVE-2021-37714Network attack vector

Denial of service via malformed parser input

Published Aug 18, 2021 · Updated Aug 4, 2024

Denial of service in jsoup before 1.14.2 allows remote attackers to hang or crash applications by supplying crafted HTML or XML. The HTML tree builder and tokenizer perform unbounded work on malformed structures, while deep parser states reach unchecked stack, null, or index errors instead of rejecting the input. Reachability requires an application to pass attacker-controlled content to a jsoup parser; effects are limited to slow parsing, an indefinitely occupied thread, or an application-level crash.

CVSS severity7.5
High
EPSS probability6.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in jsoup before 1.14.2 allows remote attackers to hang or crash applications by supplying crafted HTML or XML. The HTML tree builder and tokenizer perform unbounded work on malformed structures, while deep parser states reach unchecked stack, null, or index errors instead of rejecting the input. Reachability requires an application to pass attacker-controlled content to a jsoup parser; effects are limited to slow parsing, an indefinitely occupied thread, or an application-level crash.

The record

CVE
CVE-2021-37714
Published
Aug 18, 2021
Updated
Aug 4, 2024
Vendor
Jonathan Hedley
Product
jsoup
Classifications
CWE-835, CWE-248, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 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?

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

  1. Affected versionversion=< 1.14.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jonathan Hedley · jsoupversion=< 1.14.2

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-248Uncaught Exception
T1499.004Application or System Exploitation

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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