CVE-2020-23308Public exploitNetwork attack vector

Interpreter abort via assignment lookahead mishandling

Published Jun 10, 2021 · Updated Aug 4, 2024

Reachable assertion in JerryScript 2.2.0 allows remote attackers to abort an interpreter by submitting a crafted JavaScript expression. The expression parser mishandles assignment lookahead for a grouped left-hand-side expression, leaving its stack marker inconsistent when parser_parse_expression checks LEXER_EXPRESSION_START. Exposure requires a host application to pass remotely supplied JavaScript into an assertion-enabled build; only that process's availability is affected.

CVSS severity7.5
High
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in JerryScript 2.2.0 allows remote attackers to abort an interpreter by submitting a crafted JavaScript expression. The expression parser mishandles assignment lookahead for a grouped left-hand-side expression, leaving its stack marker inconsistent when parser_parse_expression checks LEXER_EXPRESSION_START. Exposure requires a host application to pass remotely supplied JavaScript into an assertion-enabled build; only that process's availability is affected.

The record

CVE
CVE-2020-23308
Published
Jun 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-617
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS: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-617Reachable Assertion

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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