CVE-2021-29651Network attack vector

JWT disclosure via unchecked programmatic redirect URI

Published Apr 2, 2021 · Updated Aug 3, 2024

Open redirect in Pomerium before 0.13.4 allows remote attackers to leak a logged-in victim's JWT through a crafted login URL. Programmatic access accepts an arbitrary pomerium_redirect_uri when generating a signed login URL, then appends the JWT to that destination. Exploitation requires a logged-in victim to visit the crafted URL; the token reveals identity data and enables impersonation where applications omit audience validation.

CVSS severity6.1
Medium
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Pomerium before 0.13.4 allows remote attackers to leak a logged-in victim's JWT through a crafted login URL. Programmatic access accepts an arbitrary pomerium_redirect_uri when generating a signed login URL, then appends the JWT to that destination. Exploitation requires a logged-in victim to visit the crafted URL; the token reveals identity data and enables impersonation where applications omit audience validation.

The record

CVE
CVE-2021-29651
Published
Apr 2, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-601, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 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

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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.

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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-601URL Redirection to Untrusted Site ('Open Redirect')
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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