major vulnerability· requires attention

Affects widely used Google Chrome; origin-policy bypass can expose cross-origin data and user sessions across enterprises.

Web

CVE-2026-121174

8.8

High

EPSS n/aPatch available

Chrome BackgroundFetch origin-policy bypass (pre-157.0.8103.38)

exploited

No known exploitation not in CISA KEV as of our last sync

fix

Patch available see the advisory in the references

likelihood

No EPSS score yet

Published 3 Nov 2026Analysed here 5 Nov 2026CVSS scored by CISA

common questions

Is CVE-2026-121174 being exploited?

Not confirmed. CVE-2026-121174 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.

How severe is CVE-2026-121174?

CVE-2026-121174 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-121174?

Yes. A fix has been recorded for CVE-2026-121174. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-121174 affect?

CVE-2026-121174 affects Google Chrome < 157.0.8103.38, Chromium-based browsers using BackgroundFetch. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-121174?

Update Chrome to 157.0.8103.38 or later immediately

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

Google Chrome < 157.0.8103.38Chromium-based browsers using BackgroundFetch

impact

Bypass same-origin policy via crafted HTML using BackgroundFetch, enabling unauthorized cross-origin data access or actions.

action required

Patch when possible

affected versions

Google Chrome

affected< 157.0.8103.38

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

cisa ssvc

exploitation: none
automatable: no
technical impact: total

Assessed by CISA 4 Nov 2026 (SSVC 2.0.3).

timeline

3 Nov 2026Published
4 Nov 2026CISA SSVC assessment: exploitation none · 1 day later
4 Nov 2026CVE record last updated · same day later
5 Nov 2026Analysed by vulneraibility.com · same day later

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

2 references in the CVE record: 2 links

Linkchromereleases.googleblog.com /2026/11/stable-channel-update-for-desktop.html
Linkissues.chromium.org /issues/496008447

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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