CVE-2025-2783: Google Chromium Mojo Sandbox Escape Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Google Chromium Mojo. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-03-27, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-04-17; treat that as the outer limit, not the target.
• EPSS 9.2%, percentile 95: FIRST’s model estimates a 9.2% chance of exploitation activity in the next 30 days, higher than 95% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Editorial verdict: Most can relax. Chrome CVE-2025-2783: Mojo Sandbox Escape Zero-Day — A real zero-day used for espionage in early 2025, long since fixed by Chrome's automatic updates; the lasting lesson is to make sure auto-update actually works on your fleet.

What it is

Incorrect handle provided in unspecified circumstances in Mojo in Google Chrome on Windows prior to 134.0.6998.177 allowed a remote attacker to perform a sandbox escape via a malicious file. (Chromium security severity: High)

CISA’s summary

Google Chromium Mojo on Windows contains a sandbox escape vulnerability caused by a logic error, which results from an incorrect handle being provided in unspecified circumstances. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Product: Google Chromium Mojo · Assigned by: Chrome · Published: 2025-03-26

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2025-03-27; federal due date 2025-04-17. Known ransomware use: Unknown.
• CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 9.24% probability of exploitation activity in the next 30 days; percentile 95.

Timeline

• 2025-03-25 — erroneo.us brief: Chrome CVE-2025-2783: Mojo Sandbox Escape Zero-Day
• 2025-03-26 — CVE record published by Chrome
• 2025-03-27 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2025-04-17 — CISA remediation deadline for US federal agencies
• 2026-02-26 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Listed in CISA KEV notes (chromereleases.googleblog.com) chromereleases.googleblog.com

Vulnerability records

1. CVE.org record CVE-2025-2783 cve.org
2. NVD entry CVE-2025-2783 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

1. issues.chromium.org issues.chromium.org

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