CVE-2026-118669VulnerabilityPublished 31 Oct 2026

apprise · OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client

Affects appriseSource GCVE Database

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Authoritative record:CVE-2026-118669· High 8.4

Not known to be exploited · CVSS 8.4 High : upgrade to 2.0.0_1 or 1.7.0 soon.

Data as of 31 Oct 2026, 16:51 UTC

CVSS 4.0 base score

8.4High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 4.0	8.4

Patch: Available – fixed in 2.0.0_1, 1.7.0

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: High
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the Subsequent System. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade apprise to 2.0.0_1 or 1.7.0.

Affected software

Product	Affected	Fixed in
Homebrewapprise`pkg:brew/apprise`Other threats	Affected >=1.5.0 <1.7.0 >=1.7.2 <2.0.0_1	Fixed in 1.7.0 2.0.0_1

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

Description

## Summary OAuthlib's token grant handlers can authenticate one client while authorizing the grant type and requested scopes using a different, attacker-supplied `client_id` from the request body. In affected token grant flows, `authenticate_client(request)` sets `request.client` to the authenticated client object, but OAuthlib does not require `request.client_id` to match `request.client.client_id`. If the request body already contains `client_id=...`, OAuthlib keeps that value and passes it to `validate_grant_type()` and `validate_scopes()`. As a result, an authenticated low-privilege confidential client can authenticate as itself, submit another client's `client_id` in the token request body, and cause grant and scope validation to run under that other client identity. ## Affected Surface The affected public surface is the OAuth2 token endpoint handling for: - `client_credentials` - `password` / Resource Owner Password Credentials The issue is relevant to OAuthlib provider deployments where: - the attacker has credentials for one valid lower-privilege confidential client; - another client has broader grants or scopes; - the application validator uses the `client_id` argument passed by OAuthlib in `validate_grant_type()` or `validate_scopes()`, as the `RequestValidator` API is designed to support. Deployments whose validators ignore the `client_id` argument and authorize only from `request.client` may not be affected. ## Details `Request` parses query and body parameters into request attributes, including `client_id`: - https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/common.py#L360-L397 The `RequestValidator.authenticate_client()` contract requires the integrator to authenticate the client and set `request.client`: - https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/request_validator.py#L41-L66 For the `client_credentials` grant, OAuthlib authenticates the client, verifies that `request.client` has a `client_id`, then performs grant and scope validation before normalizing `request.client_id` from `request.client.client_id`: - https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/grant_types/client_credentials.py#L106-L119 The problematic order is: ```python if not self.request_validator.authenticate_client(request): ... elif not hasattr(request.client, 'client_id'): ... self.validate_grant_type(request) request.client_id = request.client_id or request.client.client_id self.validate_scopes(request) ``` Because OAuthlib only fills `request.client_id` when it is missing, an attacker-supplied body value such as `client_id=high` survives even when `request.client.client_id == "low"`. The shared grant helper then authorizes using `request.client_id`, while passing the authenticated client object separately: - `validate_grant_type(request.client_id, request.grant_type, request.client, request)`: https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/grant_types/base.py#L152-L162 - `validate_scopes(request.client_id, request.scopes, request.client, request)`: https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/grant_types/base.py#L164-L176 The same identity split exists in the Resource Owner Password Credentials flow. After client authentication and user validation, OAuthlib validates the grant and scopes before replacing a missing `request.client_id` from `request.client.client_id`: - https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py#L87-L97 - https://github.com/oauthlib/oauthlib/blob/b3f9edffed6b370e3eb92721cea0da22ec7e18b9/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py#L178-L195 This creates an inconsistent identity state: ```text request.client.client_id == "low" # authenticated client request.client_id == "high" # attacker-supplied request parameter ``` OAuthlib then calls application authorization hooks with both values, but uses the attacker-controlled `request.client_id` as the first-class `client_id` argument. ## Impact An authenticated lower-privilege confidential client can obtain tokens authorized under another client's grant and scope policy if the application's validator follows the `RequestValidator` API and authorizes by the `client_id` argument. Concrete impact can include: - issuing access tokens with scopes not assigned to the authenticated client; - allowing a low-privilege client to use a grant type reserved for a higher-privilege client; - persisting tokens under a spoofed `client_id` while the authenticated client object is different. This is a token authorization bypass, not an unauthenticated attack. The attacker needs valid credentials for one clie

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