CVE-2020-26305Public exploitNetwork attack vector

Service interruption via exponential link-regex backtracking

Published Oct 26, 2024 · Updated Oct 28, 2024

Regular expression denial of service in Talyssonoc CommonRegexJS 0.3.1 and earlier allows remote attackers to interrupt services. The links expression used by getLinks() applies an ambiguous nested pattern to attacker-controlled URL text, causing exponential backtracking. Exposure requires a consuming application to pass remote input to the library and invoke link extraction; the resulting CPU exhaustion can block that application's event loop.

CVSS severity8.7
High
EPSS probability0.48%
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 Talyssonoc CommonRegexJS 0.3.1 and earlier allows remote attackers to interrupt services. The links expression used by getLinks() applies an ambiguous nested pattern to attacker-controlled URL text, causing exponential backtracking. Exposure requires a consuming application to pass remote input to the library and invoke link extraction; the resulting CPU exhaustion can block that application's event loop.

The record

CVE
CVE-2020-26305
Published
Oct 26, 2024
Updated
Oct 28, 2024
Vendor
Talyssonoc
Product
CommonRegexJS
Classifications
CWE-1333, CAPEC-492, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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
  2. Affected versionversion=0 <*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Talyssonoc · CommonRegexJSversion=0; version=0 <*

Published CVSS scores

6.6GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
8.7GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Green
7.5NIST NVDCVSS: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 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
CAPEC-492Regular Expression Exponential Blowup
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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