CVE-2023-28176 – CVE-2023-28176 is a memory safety vulnerability... (How to Fix)

Q: How do I fix CVE-2023-28176?

1. Open browser/email client. 2. Go to Help > About Firefox/Thunderbird. 3. Allow automatic update check. 4. Restart when prompted. 5. Verify version is 111+ (Firefox) or 102.9+ (Firefox ESR/Thunderbird).

Q: What is the severity of CVE-2023-28176?

CVE-2023-28176 has a CVSS score of 8.8 (HIGH). CVE-2023-28176 is a memory safety vulnerability in Mozilla Firefox, Firefox ESR, and Thunderbird that could allow memory corruption. With sufficient effort, attackers could potentially exploit this to execute arbitrary code on affected systems. This affects Firefox versions before 111, Firefox ESR before 102.9, and Thunderbird before 102.9.

📋 TL;DR

CVE-2023-28176 is a memory safety vulnerability in Mozilla Firefox, Firefox ESR, and Thunderbird that could allow memory corruption. With sufficient effort, attackers could potentially exploit this to execute arbitrary code on affected systems. This affects Firefox versions before 111, Firefox ESR before 102.9, and Thunderbird before 102.9.

💻 Affected Systems

Products:

Mozilla Firefox
Mozilla Firefox ESR
Mozilla Thunderbird

Versions: Firefox < 111, Firefox ESR < 102.9, Thunderbird < 102.9

Operating Systems: Windows, macOS, Linux, Android

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations are vulnerable. No special configuration required for exploitation.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or ransomware deployment.

🟠

Likely Case

Browser crash or instability; potential for limited code execution in sandboxed environment.

🟢

If Mitigated

No impact if systems are patched or browsers are not used for untrusted content.

🌐 Internet-Facing: HIGH - Web browsers process untrusted internet content by design.

🏢 Internal Only: MEDIUM - Risk exists if users visit malicious internal sites or open malicious email attachments.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: HIGH

Memory corruption vulnerabilities require sophisticated exploitation techniques but can be triggered via normal web browsing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firefox 111+, Firefox ESR 102.9+, Thunderbird 102.9+

Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2023-09/

Restart Required: Yes

Instructions:

1. Open browser/email client. 2. Go to Help > About Firefox/Thunderbird. 3. Allow automatic update check. 4. Restart when prompted. 5. Verify version is 111+ (Firefox) or 102.9+ (Firefox ESR/Thunderbird).

🔧 Temporary Workarounds

Disable JavaScript

all

Reduces attack surface by preventing JavaScript execution, which is commonly used to trigger memory corruption.

about:config → javascript.enabled = false

Use Enhanced Tracking Protection Strict Mode

all

Blocks more trackers and potentially malicious scripts.

Settings → Privacy & Security → Enhanced Tracking Protection → Strict

🧯 If You Can't Patch

Restrict browser usage to trusted websites only.
Use alternative browsers until patching is possible.

🔍 How to Verify

Check if Vulnerable:

Check browser version in Help > About Firefox/Thunderbird. If version is below 111 (Firefox) or 102.9 (Firefox ESR/Thunderbird), system is vulnerable.

Check Version:

firefox --version (Linux) or check About dialog (Windows/macOS)

Verify Fix Applied:

Confirm version is Firefox 111+ or Firefox ESR/Thunderbird 102.9+ in Help > About.

📡 Detection & Monitoring

Log Indicators:

Browser crash reports with memory access violations
Unexpected process termination in application logs

Network Indicators:

Unusual outbound connections from browser processes
Traffic to known exploit hosting domains

SIEM Query:

source="*firefox*" OR source="*thunderbird*" AND (event_type="crash" OR message="*segmentation fault*" OR message="*access violation*")

📊 Metadata

CVE ID: CVE-2023-28176

CVSS v3 Score: 8.8 (HIGH)

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

CWE: CWE-787

Published: June 2, 2023

Last Updated: January 8, 2025

🔗 References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1808352%2C1811637%2C1815904%2C1817442%2C1818674 Not Applicable,Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-09/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-10/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-11/ Vendor Advisory
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1808352%2C1811637%2C1815904%2C1817442%2C1818674 Not Applicable,Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-09/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-10/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-11/ Vendor Advisory

📤 Share & Export

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🔗 Related Vulnerabilities

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