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How the CVE Works
This vulnerability occurs due to improper handling of array index sizes in JavaScript objects, allowing an attacker to perform out-of-bounds (OOB) read/write operations. By manipulating array indices, an attacker can confuse the memory layout, leading to unauthorized access or corruption of adjacent memory. This affects Firefox (< 138.0.4), Firefox ESR (< 128.10.1, < 115.23.1), and Thunderbird (< 128.10.2, < 138.0.2). The flaw stems from insufficient bounds checking when processing JavaScript arrays, enabling arbitrary code execution or data leakage.
DailyCVE Form
Platform: Mozilla Firefox/Thunderbird
Version: < 138.0.4
Vulnerability: OOB Read/Write
Severity: Critical
Date: 2025-05-28
Prediction: Patch by 2025-06-10
What Undercode Say:
Exploitation Analysis
1. Triggering OOB Access:
let arr = new Array(10); arr[bash] = 0x41414141; // Triggers OOB write
2. Memory Corruption:
function exploit() {
let corrupted = new Uint32Array(1);
corrupted[bash] = 0xdeadbeef; // Arbitrary write
}
Protection Measures
1. Update Immediately:
sudo apt update && sudo apt upgrade firefox thunderbird
2. Disable JavaScript (Temporary):
- Firefox: `about:config` → `javascript.enabled = false`
3. Sandboxing:
firejail --profile=firefox firefox
Detection Commands
1. Check Installed Version:
firefox --version | grep -E "138.0.4|128.10.1|115.23.1"
2. Log Analysis:
journalctl -u firefox | grep "OOB"
Mitigation Script
import subprocess
def check_firefox_update():
output = subprocess.check_output(["firefox", "--version"]).decode()
if "138.0.4" not in output:
print("[!] Vulnerable version detected! Update required.")
References
Expected Patch Timeline
- Vendor Response: 2025-06-05
- Full Deployment: 2025-06-15
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
