CVE-2022-36087Public exploitNetwork attack vector

Service hang via catastrophic IPv6 regex backtracking

Published Sep 9, 2022 · Updated Apr 22, 2025

Input validation in OAuthLib 3.1.1 through 3.2.0 allows remote authenticated users to hang OAuth web applications via an IPv6 redirect URI. The IPv6address pattern in oauthlib.uri_validate nests unbounded repetitions, causing excessive regex backtracking on colon-heavy input passed to is_absolute_uri. Exposure requires an OAuth2 provider or other caller to pass a user-controlled URI into these validators, and the resulting impact is limited to service availability.

CVSS severity6.5
Medium
EPSS probability1.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Input validation in OAuthLib 3.1.1 through 3.2.0 allows remote authenticated users to hang OAuth web applications via an IPv6 redirect URI. The IPv6address pattern in oauthlib.uri_validate nests unbounded repetitions, causing excessive regex backtracking on colon-heavy input passed to is_absolute_uri. Exposure requires an OAuth2 provider or other caller to pass a user-controlled URI into these validators, and the resulting impact is limited to service availability.

The record

CVE
CVE-2022-36087
Published
Sep 9, 2022
Updated
Apr 22, 2025
Vendor
OAuthLib
Product
OAuthLib
Classifications
CWE-20, CWE-601, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 9, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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?

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

  1. Affected versionversion=>= 3.1.1, < 3.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OAuthLib · OAuthLibversion=>= 3.1.1, < 3.2.1

Published CVSS scores

5.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
6.5NISTCVSS:3.1/AV:N/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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