CVE-2024-0755 – This CVE describes memory safety bugs in Firefo... (How to Fix)

Q: How do I fix CVE-2024-0755?

1. Open Firefox/Thunderbird. 2. Click menu → Help → About Firefox/Thunderbird. 3. Application will check for updates and prompt to install. 4. Restart the application. For enterprise deployments, use your standard patch management system.

Q: What is the severity of CVE-2024-0755?

CVE-2024-0755 has a CVSS score of 8.8 (HIGH). This CVE describes memory safety bugs in Firefox, Firefox ESR, and Thunderbird that could lead to memory corruption. With sufficient effort, attackers could potentially exploit these vulnerabilities to execute arbitrary code on affected systems. All users running Firefox versions below 122, Firefox ESR below 115.7, or Thunderbird below 115.7 are vulnerable.

📋 TL;DR

This CVE describes memory safety bugs in Firefox, Firefox ESR, and Thunderbird that could lead to memory corruption. With sufficient effort, attackers could potentially exploit these vulnerabilities to execute arbitrary code on affected systems. All users running Firefox versions below 122, Firefox ESR below 115.7, or Thunderbird below 115.7 are vulnerable.

💻 Affected Systems

Products:

Firefox
Firefox ESR
Thunderbird

Versions: Firefox < 122, Firefox ESR < 115.7, Thunderbird < 115.7

Operating Systems: All platforms where affected versions run

Default Config Vulnerable: ⚠️ Yes

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

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution allowing attackers to take complete control of the affected system, install malware, steal data, or pivot to other systems.

🟠

Likely Case

Browser/application crash leading to denial of service, with potential for limited code execution in targeted attacks.

🟢

If Mitigated

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

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: HIGH

Memory corruption vulnerabilities require significant effort to weaponize, but Mozilla presumes some could be exploited to run arbitrary code.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firefox 122+, Firefox ESR 115.7+, Thunderbird 115.7+

Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2024-01/

Restart Required: Yes

Instructions:

1. Open Firefox/Thunderbird. 2. Click menu → Help → About Firefox/Thunderbird. 3. Application will check for updates and prompt to install. 4. Restart the application. For enterprise deployments, use your standard patch management system.

🔧 Temporary Workarounds

Disable JavaScript

all

Temporarily disable JavaScript to reduce attack surface while patching

about:config → javascript.enabled = false

Use alternative browser

all

Switch to a non-vulnerable browser until patches are applied

🧯 If You Can't Patch

Restrict browser usage to trusted internal sites only
Implement application whitelisting to prevent unauthorized code execution

🔍 How to Verify

Check if Vulnerable:

Check browser version in Help → About Firefox/Thunderbird and compare with affected versions

Check Version:

firefox --version or thunderbird --version

Verify Fix Applied:

Verify version is Firefox 122+, Firefox ESR 115.7+, or Thunderbird 115.7+

📡 Detection & Monitoring

Log Indicators:

Unexpected browser crashes
Memory access violation errors in system logs
Suspicious child processes spawned from browser

Network Indicators:

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

SIEM Query:

process_name:firefox.exe AND (event_id:1000 OR event_id:1001) OR process_name:thunderbird.exe AND (event_id:1000 OR event_id:1001)

📊 Metadata

CVE ID: CVE-2024-0755

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-94

Published: January 23, 2024

Last Updated: May 22, 2025

🔗 References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1868456%2C1871445%2C1873701 Issue Tracking,Permissions Required
https://lists.debian.org/debian-lts-announce/2024/01/msg00015.html Mailing List,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00022.html Mailing List,Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2024-01/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-02/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-04/ Vendor Advisory
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1868456%2C1871445%2C1873701 Issue Tracking,Permissions Required
https://lists.debian.org/debian-lts-announce/2024/01/msg00015.html Mailing List,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00022.html Mailing List,Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2024-01/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-02/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-04/ Vendor Advisory

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🔗 Related Vulnerabilities

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