CVE-2017-20165

Service interruption via inefficient newline normalization

Published Jan 9, 2023 · Updated Aug 5, 2024

Regular expression denial of service in debug-js debug 3.0.x allows attackers to interrupt Node.js applications via crafted formatted data. The %o formatter in src/node.js applies a whitespace-newline-whitespace regular expression to util.inspect output, causing excessive backtracking. Exploitation requires attacker-influenced data to reach the enabled %o formatter and can monopolize the Node.js event loop until the process becomes unresponsive.

CVSS severity3.5
Low
EPSS probability2.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in debug-js debug 3.0.x allows attackers to interrupt Node.js applications via crafted formatted data. The %o formatter in src/node.js applies a whitespace-newline-whitespace regular expression to util.inspect output, causing excessive backtracking. Exploitation requires attacker-influenced data to reach the enabled %o formatter and can monopolize the Node.js event loop until the process becomes unresponsive.

The record

CVE
CVE-2017-20165
Published
Jan 9, 2023
Updated
Aug 5, 2024
Vendor
debug-js
Product
debug
Classifications
CWE-1333, T1499.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=3.0

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

debug-js · debugversion=3.0

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.5VulDBCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
2.7VulDBAV:A/AC:L/Au:S/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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
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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