CVE-2020-36533Public exploitNetwork attack vector

Account impersonation via nonexpiring bearer tokens

Published Jun 3, 2022 · Updated Apr 15, 2025

Improper authentication in Klapp App allows remote attackers to impersonate users by replaying a captured JSON Web Token. The token handler accepts bearer tokens that have no expiration claim, while the app stores them without added protection on devices and backups. Possession of a copied token is required and grants the identity and permissions of its legitimate owner, exposing only data and actions available to that account.

CVSS severity9.8
Critical
EPSS probability1.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Klapp App allows remote attackers to impersonate users by replaying a captured JSON Web Token. The token handler accepts bearer tokens that have no expiration claim, while the app stores them without added protection on devices and backups. Possession of a copied token is required and grants the identity and permissions of its legitimate owner, exposing only data and actions available to that account.

The record

CVE
CVE-2020-36533
Published
Jun 3, 2022
Updated
Apr 15, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 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

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
3.7VulDBCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-287Improper Authentication
T1528Steal Application Access Token

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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