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VulnerabilityPublished

CVE-2026-118669: oauthlib · Incorrect Authorization

Affects oauthlibSource CVE Database V5

0

Not known to be exploited · CVSS 8.4 High : upgrade to 4.0.0 soon.

Data as of 28 Oct 2026, 21:42 UTC

CVSS 4.0 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 4.0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade oauthlib to 4.0.0.

Affected software

ProductAffectedFixed in
oauthliboauthlibAffected
  • <4.0.0
Fixed in
  • 4.0.0
PyPIoauthlibpkg:pypi/oauthlibOther threatsAffected
  • <4.0.0
Fixed in
  • 4.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade OAuthLib to version 4.0.0 or later, where this authorization flaw is fixed. Validators that authorize exclusively from request.client are not affected, but it is recommended to apply the official fix to ensure correct authorization behavior. No other mitigations are indicated by the vendor advisory.

Description

OAuthLib versions prior to 4.0.0 contain an incorrect authorization vulnerability in the client_credentials and Resource Owner Password Credentials token grant handlers. This flaw allows a lower-privilege authenticated client to impersonate another client by supplying a different client_id, potentially resulting in issuance of tokens with unauthorized grants or scopes. The issue is resolved in version 4.0.0.

References

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