CVE-2021-26194Network attack vector

Service crash via heap use after free

Published Jun 10, 2021 · Updated Aug 3, 2024

Use-after-free in JerryScript 2.4.0 allows remote attackers to interrupt service via crafted JavaScript input. The ecma_is_lexical_environment function in ecma-helpers.c accesses a heap object after it has been released while checking lexical-environment state. Exploitation requires a victim process to evaluate attacker-controlled script, and the documented impact is service interruption without confidentiality or integrity loss.

CVSS severity6.5
Medium
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in JerryScript 2.4.0 allows remote attackers to interrupt service via crafted JavaScript input. The ecma_is_lexical_environment function in ecma-helpers.c accesses a heap object after it has been released while checking lexical-environment state. Exploitation requires a victim process to evaluate attacker-controlled script, and the documented impact is service interruption without confidentiality or integrity loss.

The record

CVE
CVE-2021-26194
Published
Jun 10, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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

6.5GitLab Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

Public exploit references

No public exploit references are available in this record.

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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