CVE-2020-36373Network attack vector

Remote DoS via parse_shifts stack overflow

Published May 28, 2021 · Updated Aug 4, 2024

Stack overflow in parse_shifts in Cesanta MJS 1.20.1 allows remote attackers to cause a denial of service via a crafted file. The parse_shifts parser recursively processes crafted shift-expression input until the call stack is exhausted. A remote attacker only needs to supply the crafted file to trigger service interruption; confidentiality and data integrity impacts are not reported.

CVSS severity4.3
Medium
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack overflow in parse_shifts in Cesanta MJS 1.20.1 allows remote attackers to cause a denial of service via a crafted file. The parse_shifts parser recursively processes crafted shift-expression input until the call stack is exhausted. A remote attacker only needs to supply the crafted file to trigger service interruption; confidentiality and data integrity impacts are not reported.

The record

CVE
CVE-2020-36373
Published
May 28, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-674, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 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

4.3NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NVDCVSS:3.1/AV:L/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-674Uncontrolled Recursion
T1499Endpoint Denial of Service

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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