Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessCompromise renderer via separate bug
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DeliveryServe crafted HTML page
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ExploitWin CacheStorage timing race
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ExecutionRead memory outside sandbox
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ImpactLeak secrets to aid sandbox escape
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
|
| Exploitation Conditions | Exploitation requires the attacker to have ALREADY compromised the renderer process (a prior code-execution foothold in Chrome's sandboxed renderer, typically via a separate chained vulnerability) - this flaw alone does not grant initial access. The victim must also load attacker-controlled content (UI:R; a crafted HTML page) so the attacker can drive CacheStorage operations and win a timing-dependent race (CWE-367), which is inherently non-deterministic and may require multiple attempts. Impact is limited to reading memory outside the sandbox (confidentiality only; no integrity or availability impact) and affects Chrome versions before 155.0.8059.39 on desktop. The requirement for a pre-existing renderer compromise is the dominant limiting factor and relegates this to a chain component rather than a primary entry point. |
| Impact | This is a genuine-but-low-priority issue, and the signals are consistent in pointing that way. The vendor-assigned CVSS is 4.7 (Medium), EPSS is 0.14% (3rd percentile - very low predicted exploitation), it is NOT on the CISA KEV list, and no public exploit code was identified in the provided data. Exploitation status: no public exploit identified at time of analysis. The single most important mitigating factor is buried in the description: the attacker must ALREADY have 'compromised the renderer process.' This means the flaw (CWE-367, a TOCTOU race condition in CacheStorage enabling a read of memory outside the sandbox) is not a standalone remote compromise - it is a sandbox-boundary information-disclosure primitive useful only as a secondary link in a larger exploit chain. The provided CVSS vector (AV:N/AC:L/PR:N/UI:R) carries PR:N, which per the precision rules reads as unauthenticated; this CONFLICTS with the description's explicit requirement of a pre-compromised renderer, so authentication/privilege requirements are not cleanly represented by the vector. Chromium's scoring convention treats renderer compromise as an assumed starting state rather than a 'privilege,' which explains the PR:N, but defenders should read this as requiring a prior foothold. Scope is Changed (S:C), correctly reflecting that the impact crosses the sandbox boundary, and impact is confidentiality-only and Low (C:L/I:N/A:N). Net: real, patch-worthy, but not an emergency - standard Chrome auto-update cadence is the appropriate response. |
| Exploit ScenarioDerived | An attacker first gains code execution in Chrome's renderer process via a separate bug (e.g., a V8/HTML rendering flaw) when a victim visits a malicious page. They then serve a crafted HTML page that drives CacheStorage operations to win a timing race (CWE-367), using the resulting read to leak memory from outside the renderer sandbox - information such as pointers or secrets that aids escalating the chain toward a full sandbox escape. No public proof-of-concept was identified at the time of analysis. |
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Alert meAnalysisAIv1 – Oct 07, 2026
Out-of-sandbox memory disclosure in Google Chrome (desktop) versions prior to 155.0.8059.39 stems from a race condition (CWE-367) in the CacheStorage component, which an attacker can drive through a crafted HTML page to read memory beyond the renderer sandbox. The dominant limiting factor is that exploitation requires the attacker to have already compromised the renderer process - this flaw alone does not provide initial access and functions as a chain component rather than a primary entry point, and the victim must also load attacker-controlled content to trigger the timing-dependent race. Impact is confidentiality-only (memory read; no integrity or availability effect), the vendor has released a fixed build, EPSS is very low at 0.14% (3rd percentile), and no public exploit has been identified at time of analysis, with no CISA KEV listing.
RemediationAI
Primary fix: upgrade Google Chrome to version 155.0.8059.39 or later - this is the vendor-released patched build, distributed through Chrome's built-in auto-updater (chrome://settings/help) and standard platform packages; enterprises should push the update via their software management tooling and verify the reported version. Chromium-derived browsers should upgrade once they rebase on the corresponding upstream release. If an immediate update is not possible, the highest-value compensating control is keeping the renderer sandbox enforced with Site Isolation enabled (on by default on desktop) so a single compromised renderer cannot reach other origins' data, and treating this CVE as a chain component: detection effort should focus on the renderer-compromise prerequisites that make this race exploitable in the first place. Restricting users from loading untrusted HTML (for example, disabling JavaScript for untrusted sites or confining browsing to trusted origins) reduces exposure to the crafted-page trigger but breaks legitimate web functionality and is impractical as a general policy. There is no configuration flag that turns CacheStorage off for arbitrary content, so no clean feature-disable workaround exists; the practical trade-off is update urgency weighted against the low EPSS (0.14%) and the absence of known public exploit code.
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
CacheStorage (the Cache API backing service workers and offline caching) is implemented in Chromium's multi-process architecture, where page/renderer processes communicate with the browser process over Mojo IPC. The root cause is a time-of-check-time-of-use race (CWE-367): concurrent or interleaved CacheStorage operations can desynchronize validation of a cache entry from its later use, causing the renderer to read memory outside its sandbox boundary. The affected CPE is cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:* (all Chrome builds before the fixed release). Two different severity pictures are worth noting: NVD scores the issue CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N (4.7), while the independent assessment applies CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:N/A:N, reflecting the hard prerequisites - a prior renderer compromise (PR:L) and the non-deterministic nature of winning the race (AC:H) - alongside the user-interaction requirement (UI:R) from loading a crafted page and a scope change (S:C) because data crosses out of the sandbox. Both vectors agree the impact is limited to low confidentiality loss with no integrity or availability effect. Because the race must be won and the attacker must already hold a renderer foothold, this behaves as a sandbox-escape/data-leak enabler to be chained with an initial renderer exploit, not a standalone remote compromise.
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Requires a pre-compromised renderer (PR:L, not PR:N) and winning a non-deterministic race (AC:H); crosses the sandbox boundary (S:C) to leak memory, so C:L with no integrity or availability impact.
Primary rating from Vendor (Chrome).
CVSS VectorVendor: Chrome
Lifecycle Timeline
4DescriptionCVE.org
Race condition in CacheStorage in Google Chrome prior to 155.0.8059.39 allowed a remote attacker who had compromised the renderer process to read memory outside the sandbox via a crafted HTML page. (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-2026-93675
GHSA-h9vq-r34h-q3fm
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB