CVE-2021-39176Public exploitNetwork attack vector

Application outage via unclosed ICU charset detector

Published Aug 31, 2021 · Updated Aug 4, 2024

Memory leak in Sonicdoe detect-character-encoding 0.3.0 and earlier allows attackers to exhaust a consuming application's memory. The DetectCharacterEncoding method opens an ICU charsetDetector but fails to call ucsdet_close on successful and error-return paths, retaining its storage after each invocation. Repeated invocation can exhaust the hosting Node.js process; network reachability depends on a consuming program exposing the library.

CVSS severity7.5
High
EPSS probability1.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Sonicdoe detect-character-encoding 0.3.0 and earlier allows attackers to exhaust a consuming application's memory. The DetectCharacterEncoding method opens an ICU charsetDetector but fails to call ucsdet_close on successful and error-return paths, retaining its storage after each invocation. Repeated invocation can exhaust the hosting Node.js process; network reachability depends on a consuming program exposing the library.

The record

CVE
CVE-2021-39176
Published
Aug 31, 2021
Updated
Aug 4, 2024
Vendor
Sonicdoe
Product
detect-character-encoding
Classifications
CWE-401, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 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=< 0.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sonicdoe · detect-character-encodingversion=< 0.3.1

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.2GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:O/RC:C
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.003Application Exhaustion Flood

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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