CVE-2026-87561VulnerabilityPublished 09/09/2026Updated 09/10/2026

CVE-2026-87561: Incorrect authorization in Google Chrome

Affects Google ChromeSource GCVE Database

ghsa-pwfx-cvw3-39gw

Not known to be exploited · CVSS 4.3 Medium : monitor for a fix to Google Chrome.

Data as of 10/24/2026, 20:40:32 UTC

CVSS 3.1 base score

4.3Medium

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

Exploitation: Not in CISA KEV, no exploitation reported
EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

What to do

Affected software

Product	Affected	Fixed in
Google Chrome	Affected =153.0.8010.36 <153.0.8010.36	Fixed in 153.0.8010.36

AI-suggested

A fix is available in Google Chrome version 153.0.8010.36. Users and administrators should update to this version or later to remediate the vulnerability. Since this is not a cloud service, remediation depends on applying the update locally. No additional mitigation guidance is provided.

Description

CVE-2026-87561 is a vulnerability in Google Chrome's Web Authentication prior to version 153.0.8010.36. It allows a remote attacker to bypass the web origin policy via a crafted Chrome extension due to incorrect authorization. The issue is classified with a medium severity and a CVSS score of 4.3, indicating limited impact primarily on integrity without confidentiality or availability effects.

Impact

The vulnerability allows a remote attacker to bypass the web origin policy via a malicious Chrome extension, potentially leading to unauthorized actions or integrity violations within the browser context. There is no impact on confidentiality or availability according to the CVSS vector. The issue is limited to integrity impact and requires user interaction (UI:R).

Summary

This vulnerability involves incorrect authorization in the Web Authentication component of Google Chrome before version 153.0.8010.36. An attacker can exploit this flaw by using a specially crafted Chrome extension to bypass the web origin policy, which normally restricts web content from interacting with resources from different origins. The Chromium security team has rated this issue as low severity internally, but the CVSS score assigned is 4.3, reflecting a medium severity level. The vulnerability is tracked as CWE-863 (Incorrect Authorization). No known exploits are reported in the wild, and no official patch links were provided in the input data.

Weaknesses

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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