VulnerabilityPublished 27 Oct 2026

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

Affects gcalcliSource GCVE Database

Not known to be exploited · CVSS 8.5 High : upgrade to 4.5.1_14 soon.

Data as of 27 Oct 2026, 23:14 UTC

CVSS 3.1 base score

8.5High

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

Patch: Available – fixed in 4.5.1_14

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 27 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 gcalcli to 4.5.1_14.

Affected software

Product	Affected	Fixed in
Homebrewgcalcli`pkg:brew/gcalcli`Other threats	Affected >=4.5.1_3 <4.5.1_14	Fixed in 4.5.1_14

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 4.5.1_14 or later, where the device_code validation is properly implemented and public clients are correctly handled in the device authorization grant flow. Applying this official fix will prevent issuance of bearer tokens without valid device_code parameters. No other mitigation is recommended as the fix addresses the root cause.

Description

OAuthLib versions from 4.5.1_3 up to but not including 4.5.1_14 contain a vulnerability in the device workflow implementation of the OAuth 2.0 device authorization grant (RFC 8628). The token endpoint does not properly validate the device_code parameter, allowing an attacker who knows a valid client ID for a public client to obtain a bearer token without a valid device_code. This flaw arises because the DeviceCodeGrant.validate_token_request method lacks proper device_code validation and mishandles public clients. A fix is available in version 4.5.1_14.

Impact

An attacker who knows a valid client ID for a public client configured for the device workflow can obtain a bearer token from the token endpoint without presenting a valid device_code. This bypasses the intended security checks of the OAuth 2.0 device authorization grant flow, potentially allowing unauthorized access to protected resources. The vulnerability impacts confidentiality and integrity of the OAuth tokens issued by affected versions of OAuthLib.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 23:14 UTC

Technical details

References

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