CVE-2024-53861Public exploitNetwork attack vector

Issuer validation bypass via substring comparison

Published Nov 29, 2024 · Updated Dec 2, 2024

Incorrect issuer validation in PyJWT 2.10.0 allows remote authenticated users to pass a partially matching JWT issuer claim. The _validate_iss method treats the configured issuer string as a generic Sequence and uses membership testing, so an issuer that is only a substring passes validation. A valid signature and issuer validation configured with a single string are required; the flaw does not bypass signature verification, but it can admit a token from the wrong issuer.

CVSS severity2.1
Low
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect issuer validation in PyJWT 2.10.0 allows remote authenticated users to pass a partially matching JWT issuer claim. The _validate_iss method treats the configured issuer string as a generic Sequence and uses membership testing, so an issuer that is only a substring passes validation. A valid signature and issuer validation configured with a single string are required; the flaw does not bypass signature verification, but it can admit a token from the wrong issuer.

The record

CVE
CVE-2024-53861
Published
Nov 29, 2024
Updated
Dec 2, 2024
Vendor
Jose Padilla
Product
PyJWT
Classifications
CWE-697
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Dec 2, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== 2.10.0
  2. Affected versionversion=2.10.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jose Padilla · PyJWTversion== 2.10.0; version=2.10.0

Published CVSS scores

2.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
2.2GitHub CNACVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-697Incorrect Comparison

Public exploit references

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Technologies

Your stack

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Your stack

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