CVE-2021-23900Public exploitNetwork attack vector

Denial of service via malformed numeric input

Published Jan 13, 2021 · Updated Aug 3, 2024

Denial of service in OWASP json-sanitizer before 1.2.2 allows remote attackers to interrupt applications with crafted JSON-like input. The JsonSanitizer.normalizeNumber path accumulates arbitrary-length hexadecimal and octal tokens in a signed long, allowing overflow and invalid output, while other malformed-token paths can throw undeclared exceptions. Exposure requires an application to process attacker-controlled content without safely containing invalid JSON or exceptions.

CVSS severity7.5
High
EPSS probability2.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OWASP json-sanitizer before 1.2.2 allows remote attackers to interrupt applications with crafted JSON-like input. The JsonSanitizer.normalizeNumber path accumulates arbitrary-length hexadecimal and octal tokens in a signed long, allowing overflow and invalid output, while other malformed-token paths can throw undeclared exceptions. Exposure requires an application to process attacker-controlled content without safely containing invalid JSON or exceptions.

The record

CVE
CVE-2021-23900
Published
Jan 13, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-248, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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-248Uncaught Exception
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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