CVE-2025-39946

CRITICAL

Linux Kernel 6.0-6.1.153, 6.2-6.6.107, 6.7-6.12.48, 6.13-6.16.8 - Denial of Service via TLS Stream Header Parsing

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2025-39946. PoCs published by farazsth98.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2025-39946, targeting a Linux kernel vulnerability in the TLS subsystem. The exploit leverages memory corruption via crafted TLS packets to overwrite page table entries and manipulate the `core_pattern` kernel parameter for privilege escalation.

Description

In the Linux kernel, the following vulnerability has been resolved: tls: make sure to abort the stream if headers are bogus Normally we wait for the socket to buffer up the whole record before we service it. If the socket has a tiny buffer, however, we read out the data sooner, to prevent connection stalls. Make sure that we abort the connection when we find out late that the record is actually invalid. Retrying the parsing is fine in itself but since we copy some more data each time before we parse we can overflow the allocated skb space. Constructing a scenario in which we're under pressure without enough data in the socket to parse the length upfront is quite hard. syzbot figured out a way to do this by serving us the header in small OOB sends, and then filling in the recvbuf with a large normal send. Make sure that tls_rx_msg_size() aborts strp, if we reach an invalid record there's really no way to recover.

Exploits (1)

github WORKING POC 33 stars
by farazsth98 · cpoc
https://github.com/farazsth98/exploit-CVE-2025-39946

This repository contains a functional exploit for CVE-2025-39946, targeting a Linux kernel vulnerability in the TLS subsystem. The exploit leverages memory corruption via crafted TLS packets to overwrite page table entries and manipulate the `core_pattern` kernel parameter for privilege escalation.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: Linux kernel (lts-6.12.48)
No auth needed
Prerequisites: Linux kernel version lts-6.12.48 or similar · TLS socket support · Ability to trigger memory pressure
devstral-2 · analyzed Feb 19, 2026 Full analysis →

Scores

CVSS v3 9.8
EPSS 0.0003
EPSS Percentile 10.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

Status published
Products (18)
linux/Kernel 6.0.0 - 6.1.154linux
linux/Kernel 6.13.0 - 6.16.9linux
linux/Kernel 6.2.0 - 6.6.108linux
linux/Kernel 6.7.0 - 6.12.49linux
Linux/Linux < 6.0
Linux/Linux 6.0
Linux/Linux 6.1.154 - 6.1.*
Linux/Linux 6.12.49 - 6.12.*
Linux/Linux 6.16.9 - 6.16.*
Linux/Linux 6.17
... and 8 more
Published Oct 04, 2025
Tracked Since Feb 18, 2026