Remote code execution in Google Chrome (widely deployed browser) enabling host compromise; impacts organizations using Chrome and merits broad IT attention.
CVE-2026-121257
Use-after-free in Chrome TabStrip allows RCE via crafted extension
Is CVE-2026-121257 being exploited?
Not confirmed. CVE-2026-121257 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-2026-121257?
CVE-2026-121257 is rated Critical with a CVSS score of 9.6. 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-2026-121257?
Yes. A fix has been recorded for CVE-2026-121257. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-121257 affect?
CVE-2026-121257 affects Google Chrome desktop versions prior to 157.0.8103.38 (Windows/macOS/Linux). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-121257?
Update Chrome to 157.0.8103.38+ and restrict/uninstall untrusted extensions
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution outside the sandbox via a crafted Chrome extension, enabling full host compromise and arbitrary code execution.
Immediate action required
- 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 · same day later
- 5 Nov 2026CVE record last updated · 1 day later
- 5 Nov 2026Analysed by vulneraibility.com · same day later
- Linkchromereleases.googleblog.com /2026/11/stable-channel-update-for-desktop.html
- Linkissues.chromium.org /issues/567672825
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.