Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessTrick user into installing crafted extension
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ExploitExtension observes scroll-based side channel
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ExecutionInfer cross-origin data via discrepancy
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ImpactExfiltrate leaked cross-origin information
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V6 - Authentication Timing-safe comparisons
|
| Exploitation Conditions | Exploitation requires the victim to install a crafted (attacker-controlled) Chrome extension, and is limited to Chrome versions prior to 155.0.8059.39 on the desktop stable channel. The user-interaction requirement (installing/running the malicious extension) and high attack complexity (AC:H) are the primary limiting factors; the flaw cannot be triggered by merely visiting a web page without the malicious extension present. Impact is confined to disclosure of cross-origin data (C:L) with no integrity or availability effect. Auto-update further limits the exposure window. |
| Impact | This is a genuinely low-priority issue despite affecting a ubiquitous product. The CVSS 3.1 base score is only 3.1 (Low), driven by a network vector (AV:N) but tempered by high attack complexity (AC:H), required user interaction (UI:R), and limited confidentiality impact only (C:L/I:N/A:N). All exploitation signals point the same direction and are mutually consistent: SSVC reports Exploitation 'none', Automatable 'no', and Technical Impact 'partial', which aligns with the low CVSS and the limited C:L impact. There is no CISA KEV listing and no public exploit code referenced in the input, so exploitation status is 'no public exploit identified at time of analysis.' No EPSS score was provided in the input, so probabilistic exploitation likelihood could not be cross-referenced. The key real-world limiter is that exploitation requires a crafted (malicious) Chrome extension to be installed, which is a high bar and inconsistent with casual mass exploitation. Chromium itself rated this 'Medium' severity, slightly above the NVD 3.1 Low; this is a modest, expected discrepancy and not a conflict worth escalation. Net assessment: a high-prevalence product but a low real-risk, information-disclosure-only flaw - patch via normal browser-update cadence rather than emergency response. |
| Exploit ScenarioDerived | An attacker publishes or convinces a victim to install a crafted Chrome extension that abuses an observable timing/behavioral discrepancy in Chrome's scroll handling to infer cross-origin data the extension should not be able to read. Because the browser auto-updates, the window of exposure is narrow, and no public exploit code is referenced. The high attack complexity (AC:H) and need for the user to install the extension (UI:R) make opportunistic exploitation unlikely. |
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Alert meAnalysisAIv1 – Oct 07, 2026
Cross-origin information disclosure in Google Chrome (desktop stable channel) affects releases prior to 155.0.8059.39, where an observable discrepancy in the browser's Scroll behavior can be measured to infer data from other origins. Exploitation is not possible simply by visiting a web page: the attacker must first get the victim to install a crafted Chrome extension, which is the user-interaction requirement (UI:R) and the main driver of the high attack-complexity rating (AC:H) in the assessed vector CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N. No public exploit code has been identified at time of analysis, CISA's SSVC assessment records Exploitation as 'none' and Automatable as 'no' with partial technical impact, and the impact is confined to a low-confidentiality leak with no integrity or availability effect. This is a genuinely low-priority issue despite affecting a ubiquitous product, and the practical exposure window is further narrowed by Chrome's automatic update mechanism.
RemediationAI
Vendor-released patch: Google Chrome 155.0.8059.39 - upgrade to that version or later, which on the stable channel normally happens automatically; verify the installed build via chrome://version and force an update check from chrome://settings/help on managed or offline fleets, and track deployment against the release notes at https://chromereleases.googleblog.com/2026/10/stable-channel-update-for-desktop_086471744.html. Because exploitation hinges entirely on a malicious extension being installed, the most effective compensating controls are browser policy restrictions on extensions rather than anything network-facing: apply ExtensionInstallBlocklist (with the allowlist variant ExtensionAllowlist, or ExtensionSettings with installation_mode 'blocked'/'allowed') via enterprise policy to prevent users from installing unreviewed extensions, accepting the operational trade-off that legitimate user-installed extensions will also be blocked and must be explicitly whitelisted; additionally disable developer mode on managed endpoints to prevent unpacked extension sideloading, at the cost of hindering internal extension development. If policy control is unavailable, user education against installing extensions from untrusted sources is the only remaining mitigating measure, and it is weak. There is no server-side or configuration workaround that closes the underlying observable discrepancy itself, so patching remains the only complete fix; given the low 3.1 severity, this should be scheduled with routine Chrome update cycles rather than treated as an emergency, though the update should not be deferred indefinitely.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
The flaw is an instance of CWE-203 (Observable Discrepancy), a side-channel class in which two logically distinct states of a system produce externally measurable differences that reveal information the same-origin policy is meant to protect. In this case the observable is scroll-related behavior in Chromium's rendering/compositing pipeline - measurable scroll extents, scroll anchoring or layout responses can vary depending on cross-origin content, letting a caller infer properties of a cross-origin document it cannot read directly. The CVSS vector confirms the network attack vector with no required privileges (PR:N), but the combination of UI:R and AC:H reflects that the attacker needs a privileged foothold inside the browser: a crafted extension with host permissions or content-script injection is the realistic delivery mechanism, since a plain web page cannot reliably set up or observe the necessary state. It affects the Google Chrome desktop stable channel (CPE cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*), with the version ceiling of 155.0.8059.39 supplied by ENISA EUVD; the MITRE CPE string does not itself encode that bound. Chromium rated the issue Medium severity and the resulting CVSS base score is only 3.1, consistent with an information-disclosure side channel rather than memory corruption or code execution.
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Severity by source
AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
Attacker needs no privileges (PR:N) but relies on the user installing a crafted extension (UI:R) and a hard-to-control side channel (AC:H); only limited cross-origin data leaks (C:L), no integrity/availability impact.
Primary rating from Vendor (Chrome).
CVSS VectorVendor: Chrome
Lifecycle Timeline
4DescriptionCVE.org
Observable discrepancy in Scroll in Google Chrome prior to 155.0.8059.39 allowed a remote attacker to obtain cross-origin data via a crafted Chrome extension. (Chromium security severity: Medium)
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
EUVD-2026-93583
GHSA-4rrp-4wx7-c4vv
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB