CVE-2023-29827Public exploitNetwork attack vector

Remote code execution via closeDelimiter code splicing

Published May 4, 2023 · Updated Jan 29, 2025

Server-side template injection in EJS 3.1.9 allows remote attackers to execute arbitrary code through a crafted closeDelimiter value. When an application passes attacker-controlled render data as view options, the compiler inserts closeDelimiter-derived text into generated JavaScript without escaping code-significant characters. Exploitation requires exposing template content and render options to untrusted input, a usage the EJS maintainer classifies as inherently insecure and outside the project's security scope.

CVSS severity9.8
Critical
EPSS probability5.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side template injection in EJS 3.1.9 allows remote attackers to execute arbitrary code through a crafted closeDelimiter value. When an application passes attacker-controlled render data as view options, the compiler inserts closeDelimiter-derived text into generated JavaScript without escaping code-significant characters. Exploitation requires exposing template content and render options to untrusted input, a usage the EJS maintainer classifies as inherently insecure and outside the project's security scope.

The record

CVE
CVE-2023-29827
Published
May 4, 2023
Updated
Jan 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 29, 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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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

T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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