CVE-2026-25547Public exploitNetwork attack vector

Node.js process crash via unbounded brace expansion

Published Feb 4, 2026 · Updated Feb 4, 2026

@isaacs/brace-expansion before 5.0.1 allows remote attackers to crash Node.js processes through crafted numeric brace ranges. Its expand function eagerly and synchronously materializes every combination without an expansion or complexity limit, causing exponential CPU and memory consumption. A downstream application must pass attacker-controlled patterns to the library; one small payload can block its event loop and exhaust its heap.

CVSS severity8.7
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

@isaacs/brace-expansion before 5.0.1 allows remote attackers to crash Node.js processes through crafted numeric brace ranges. Its expand function eagerly and synchronously materializes every combination without an expansion or complexity limit, causing exponential CPU and memory consumption. A downstream application must pass attacker-controlled patterns to the library; one small payload can block its event loop and exhaust its heap.

The record

CVE
CVE-2026-25547
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
Julian Gruber
Product
brace-expansion
Classifications
CWE-1333, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2026Record 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=< 5.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Julian Gruber · brace-expansionversion=< 5.0.1

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA: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 exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499Endpoint Denial of Service

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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