CVE-2020-23259Public exploitNetwork attack vector

Interpreter crash via null url_encode argument

Published Apr 4, 2023 · Updated Feb 14, 2025

NULL pointer dereference in Jsish 3.0.11 and earlier allows remote attackers to crash the interpreter through a crafted script. The encodeURI path passes a null string into url_encode, which forwards it to Jsi_Strlen and ultimately strlen without a null check. The application must evaluate attacker-supplied JavaScript; the demonstrated consequence is an interpreter segmentation fault.

CVSS severity7.5
High
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Jsish 3.0.11 and earlier allows remote attackers to crash the interpreter through a crafted script. The encodeURI path passes a null string into url_encode, which forwards it to Jsi_Strlen and ultimately strlen without a null check. The application must evaluate attacker-supplied JavaScript; the demonstrated consequence is an interpreter segmentation fault.

The record

CVE
CVE-2020-23259
Published
Apr 4, 2023
Updated
Feb 14, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS: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-476NULL Pointer Dereference
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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