VulnerabilityPublished 28 Oct 2026Updated 29 Oct 2026

CVE-2026-49272: OAuthLib · Bearer token can be retrieved as long as client knows a valid client ID for device workflow

Affects hermes-agentSource GCVE Database

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Not known to be exploited · CVSS 8.5 High.

Data as of 29 Oct 2026, 21:45 UTC

CVSS 3.1 base score

8.5High

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: High
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 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 29 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

Affected software

Product	Affected	Fixed in
Homebrewhermes-agent`pkg:brew/hermes-agent`Other threats	Affected >=0.21.6 >=2026.9.14 <=2026.9.24	Fixed in–

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AI-suggested

Until a fix is available, users should carefully validate client configurations and monitor OAuthLib updates for a fix that adds proper device_code validation in DeviceCodeGrant.validate_token_request. Avoid using vulnerable versions in production environments if possible.

Description

OAuthLib's implementation of the OAuth 2.0 device authorization grant (RFC 8628) contains a vulnerability where the token endpoint does not validate the device_code parameter. This allows an attacker who knows a valid client ID enabled for the device workflow to obtain a bearer token without a valid device_code. The issue arises because DeviceCodeGrant.validate_token_request lacks proper validation of the device_code parameter, unlike other grant types. This affects OAuthLib versions >=0.21.6 and versions >=2026.9.14 <=2026.9.24. The vulnerability has a high severity with a CVSS score of 8.5.

Impact

An attacker who knows a valid client ID for a public client configured for the device workflow can obtain a bearer token without presenting a valid device_code. This compromises the integrity of the OAuth device authorization flow, potentially allowing unauthorized access to protected resources. The impact includes unauthorized token issuance with limited privileges (client-level access), which can lead to information disclosure or privilege escalation depending on the client permissions.

Summary

The OAuthLib library's device authorization grant implementation does not validate the device_code parameter in token requests as required by RFC 8628. An attacker with knowledge of a valid client ID configured for the device workflow can call the token endpoint with any device_code value and receive a bearer token. This occurs because DeviceCodeGrant.validate_token_request does not verify the presence or validity of device_code, unlike the authorization code grant which performs such checks. The vulnerability affects OAuthLib versions >=0.21.6 and >=2026.9.14 through 2026.9.24. No public exploits or cloud service mitigations are noted.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 21:45 UTC

Technical details

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