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Google Chrome EUVDEUVD-2026-65873

| CVE-2026-78991 MEDIUM
Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367)
2026-08-25 Chrome GHSA-mx4f-pjm3-x629
Medium
Disputed · 5.3 Vendor: Chrome
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    User visits attacker-crafted HTML page
  2. Delivery
    Separate renderer exploit achieves renderer compromise
  3. Exploit
    Race condition triggered in WebProtect subsystem
  4. Execution
    Timing window won between check and use
  5. Impact
    Sensitive information leaked to attacker

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
Exploitation Conditions

Exploitation requires two compounding conditions: first, the attacker must have already achieved compromise of the Chrome renderer process (a significant prerequisite typically requiring a separate, distinct browser vulnerability); second, the victim user must navigate to or be served a crafted HTML page. The renderer compromise prerequisite is the dominant limiting factor - it places this vulnerability firmly in multi-stage, targeted attack territory rather than accessible to unsophisticated attackers. The race condition's AC:H rating further constrains reliable exploitation, as the attacker must win a narrow timing window. No special browser configuration or non-default settings are required beyond these conditions. Exploitation is limited to the confidentiality impact category (C:H); there is no integrity or availability component, so data exfiltration is the realistic end-state, not code execution through this specific CVE alone.

Impact

Real-world risk is moderate-to-low despite the High confidentiality impact in CVSS. The official CVSS 3.1 score of 5.3 (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N) captures several limiting factors: high attack complexity due to the race condition timing window, required user interaction, and critically, the implicit prerequisite that the renderer process must already be compromised. This prerequisite - not reflected as PR in CVSS but material to real-world risk - effectively makes this a second-stage vulnerability requiring a separate renderer compromise exploit to chain with. EPSS at 0.29% (22nd percentile) corroborates low exploitation likelihood. The vulnerability is not listed in CISA KEV, no POC code has been identified, and the patch has already been shipped. For organizations running patched Chrome deployments, risk is negligible. For those lagging on updates, this becomes relevant only in the context of a broader multi-stage attack. No conflicting signals between CVSS and description are observed - the data is internally consistent.

Exploit ScenarioDerived

An attacker operating within an already-compromised Chrome renderer process - achieved via a separate vulnerability - serves or manipulates a crafted HTML page to trigger a race condition in the WebProtect subsystem, winning the timing window to read sensitive memory or data protected by WebProtect before the security check resolves. No public exploit code for this specific race condition has been identified, and the high attack complexity means reliable exploitation requires precise timing, making opportunistic mass exploitation unlikely.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 26, 2026

WebProtect race condition in Google Chrome prior to 152.0.7977.65 exposes sensitive information to attackers who have already achieved renderer process compromise. The flaw (CWE-367 TOCTOU) enables a second-stage information disclosure step within a broader browser exploitation chain, requiring a victim to interact with a crafted HTML page. No public exploit code has been identified and EPSS sits at 0.29% (22nd percentile), indicating limited real-world exploitation pressure at this time; a vendor patch is available.

RemediationAI

Update Google Chrome to version 152.0.7977.65 or later, as released in the stable channel update detailed at http://chromereleases.googleblog.com/2026/08/stable-channel-update-for-desktop_0256176589.html. Chrome's auto-update mechanism will typically apply this in the background; administrators managing enterprise fleets should verify deployment via Chrome Browser Cloud Management or equivalent. As a compensating control where immediate patching is not feasible, restricting access to untrusted or external web content reduces exposure since the attack requires user navigation to a crafted HTML page. Disabling JavaScript or using strict site isolation policies would partially mitigate the race window, but these carry significant usability trade-offs. Because exploitation also requires a pre-existing renderer compromise, organizations should prioritize patching the full Chrome binary to eliminate the entire renderer attack surface, not just this individual race condition.

Affected VersionsENISA

Chrome 152.0.7977.65 <152.0.7977.65

Affected Packages

euvd chrome fix: 152.0.7977.65

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The vulnerability resides in WebProtect, a Chrome security subsystem, and is classified as CWE-367 (Time-of-check Time-of-use / TOCTOU race condition). In TOCTOU flaws, a window exists between when a resource or security decision is checked and when it is used, allowing a concurrent thread or process to alter the state in between. The affected CPE is cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:* covering all Chrome versions prior to 152.0.7977.65 across all platforms. Because the vulnerability requires a pre-existing compromised renderer process, it sits within Chrome's sandbox boundary - the renderer sandbox is intentionally isolated, and this race condition represents a mechanism to leak information from a more privileged context into the compromised renderer's reach. The CVSS AC:H reflects both the inherent timing requirements of a race condition and the multi-stage nature of exploitation.

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Severity by source

Sources disagree (Medium–Critical)
Vendor (Chrome) PRIMARY 5.3 MEDIUM
AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
vuln.today AI 5.3 MEDIUM

Network delivery via crafted HTML page; AC:H for race condition timing and renderer-compromise prerequisite; UI:R required; confidentiality-only impact.

3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
4.0 AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
SUSE CRITICAL

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: Chrome

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

3
CVSS changed
Aug 26, 2026 - 20:23 NVD
5.3 (MEDIUM)
CVE Published
Aug 25, 2026 - 20:10 cve.org
MEDIUM 5.3
CVE Published
Aug 25, 2026 - 20:10 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

Race condition in WebProtect in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to obtain sensitive information via a crafted HTML page. (Chromium security severity: Medium)

Threat Intelligence Overview

EPSS Score
0.3%
Top 78% exploitable
Prevalence
Ubiquitous
dominant global desktop browser, installed across billions of devices
Data Quality
5 sources
Confidence: Medium

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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
High
Technical Impact
Partial

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Vendor StatusVendor

SUSE

Severity: Critical
Product Status
SUSE Package Hub 15 SP7 Fixed
openSUSE Leap 16.0 Fixed
openSUSE Tumbleweed Fixed
SUSE Package Hub 15 SP7 Affected

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