CVE-2025-38574

Q: What is the severity of CVE-2025-38574?

CVE-2025-38574 has a CVSS score of 7.8 (HIGH). A kernel memory disclosure vulnerability in the Linux kernel's PPTP implementation allows reading uninitialized data from kernel memory. This affects systems using PPTP (Point-to-Point Tunneling Protocol) networking. Attackers could potentially leak sensitive kernel memory contents.

7.8 HIGH

📋 TL;DR

A kernel memory disclosure vulnerability in the Linux kernel's PPTP implementation allows reading uninitialized data from kernel memory. This affects systems using PPTP (Point-to-Point Tunneling Protocol) networking. Attackers could potentially leak sensitive kernel memory contents.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not specified in CVE, but references indicate multiple stable kernel versions need patching

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if PPTP networking is enabled and in use. Many modern systems disable PPTP by default due to security concerns.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel memory disclosure could lead to information leaks including sensitive data, cryptographic keys, or memory addresses that could aid further exploitation.

🟠

Likely Case

Information disclosure of uninitialized kernel memory, potentially revealing system state or sensitive data fragments.

🟢

If Mitigated

Minimal impact if PPTP is disabled or systems are not using PPTP networking.

🌐 Internet-Facing: MEDIUM - Requires PPTP service exposure and network access to exploit.

🏢 Internal Only: LOW - Requires internal network access and PPTP usage.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires network access to PPTP service and ability to send specially crafted packets. Found via syzbot fuzzing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes referenced in git commits

Vendor Advisory: https://git.kernel.org/stable/c/1a04db0fd75cb6034fc27a56b67b3b8b9022a98c

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.

🔧 Temporary Workarounds

Disable PPTP

linux

Disable PPTP networking if not required

modprobe -r ppp_mppe pptp
echo 'blacklist pptp' >> /etc/modprobe.d/blacklist.conf
echo 'blacklist ppp_mppe' >> /etc/modprobe.d/blacklist.conf

Block PPTP network traffic

linux

Block PPTP ports at firewall

iptables -A INPUT -p tcp --dport 1723 -j DROP
iptables -A INPUT -p gre -j DROP

🧯 If You Can't Patch

Disable PPTP service completely
Implement network segmentation to isolate PPTP traffic

🔍 How to Verify

Check if Vulnerable:

Check if PPTP module is loaded: lsmod | grep -E 'pptp|ppp_mppe'

Check Version:

uname -r

Verify Fix Applied:

Check kernel version against patched versions from git commits, verify PPTP is disabled or system is patched

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
System crash dumps related to PPTP
Unusual PPTP connection attempts

Network Indicators:

Unusual PPTP traffic patterns
Multiple connection attempts to TCP port 1723

SIEM Query:

source="kernel" AND "pptp" AND ("panic" OR "BUG" OR "uninit")

📊 Metadata

CVE ID: CVE-2025-38574

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-908

EPSS Score: 0.01% exploit probability (2.4th percentile)

Published: August 19, 2025

Last Updated: January 9, 2026

🔗 References

https://git.kernel.org/stable/c/1a04db0fd75cb6034fc27a56b67b3b8b9022a98c Patch
https://git.kernel.org/stable/c/26672f1679b143aa34fca0b6046b7fd0c184770d Patch
https://git.kernel.org/stable/c/5005d24377378a20e5c0e53052fc4ebdcdcbc611 Patch
https://git.kernel.org/stable/c/504cc4ab91073d2ac7404ad146139f86ecee7193 Patch
https://git.kernel.org/stable/c/5de7513f38f3c19c0610294ee478242bea356f8c Patch
https://git.kernel.org/stable/c/97b8c5d322c5c0038cac4bc56fdbe237d0be426f Patch
https://git.kernel.org/stable/c/b7dcda76fd0615c0599c89f36873a6cd48e02dbb Patch
https://git.kernel.org/stable/c/de9c4861fb42f0cd72da844c3c34f692d5895b7b Patch
https://git.kernel.org/stable/c/ea99b88b1999ebcb24d5d3a6b7910030f40d3bba Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory,Mailing List
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory,Mailing List

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Debian Linux by Debian

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Disable PPTP

Block PPTP network traffic

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

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