CVE-2026-2739Public exploitNetwork attack vector

Process hang via zero-width bit masking

Published Feb 20, 2026 · Updated Feb 20, 2026

Infinite loop in Fedor Indutny bn.js before 5.2.3 allows remote attackers to hang a process via code that invokes maskn(0). Calling maskn(0) sets the BN instance's length to zero, violating the minimum length invariant; later toString(), divmod(), and related methods never terminate. Exploitation requires an application to let untrusted input drive this library operation, and the bounded consequence is a process hang.

CVSS severity5.3
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in Fedor Indutny bn.js before 5.2.3 allows remote attackers to hang a process via code that invokes maskn(0). Calling maskn(0) sets the BN instance's length to zero, violating the minimum length invariant; later toString(), divmod(), and related methods never terminate. Exploitation requires an application to let untrusted input drive this library operation, and the bounded consequence is a process hang.

The record

CVE
CVE-2026-2739
Published
Feb 20, 2026
Updated
Feb 20, 2026
Vendor
Elliptic Project
Product
bn.js
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 20, 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=0 <5.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Elliptic Project · bn.jsversion=0 <5.2.3

Published CVSS scores

5.5SnykCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
5.3SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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

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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