CVE-2026-23416

MEDIUM

mm/mseal: update VMA end correctly on merge

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 4 public exploits for CVE-2026-23416. PoCs published by adminlove520, TreasureBoy520, XZ1r0.

AI-analyzed exploit summary This repository contains a functional proof-of-concept exploit for CVE-2026-23416, a vulnerability in the Linux kernel's mm/mseal subsystem affecting versions 6.17 through 7.0-rc5. The exploit demonstrates a logic error in mseal_apply() where stale VMA end values lead to incorrect VM_SEALED application, potentially undermining memory protection guarantees.

Description

In the Linux kernel, the following vulnerability has been resolved: mm/mseal: update VMA end correctly on merge Previously we stored the end of the current VMA in curr_end, and then upon iterating to the next VMA updated curr_start to curr_end to advance to the next VMA. However, this doesn't take into account the fact that a VMA might be updated due to a merge by vma_modify_flags(), which can result in curr_end being stale and thus, upon setting curr_start to curr_end, ending up with an incorrect curr_start on the next iteration. Resolve the issue by setting curr_end to vma->vm_end unconditionally to ensure this value remains updated should this occur. While we're here, eliminate this entire class of bug by simply setting const curr_[start/end] to be clamped to the input range and VMAs, which also happens to simplify the logic.

Exploits (4)

github WORKING POC 3 stars
by adminlove520 · pythonpoc
https://github.com/adminlove520/CVE-Poc_All_in_One/tree/main/2026/CVE-2026-23416

This repository contains a functional proof-of-concept exploit for CVE-2026-23416, a vulnerability in the Linux kernel's mm/mseal subsystem affecting versions 6.17 through 7.0-rc5. The exploit demonstrates a logic error in mseal_apply() where stale VMA end values lead to incorrect VM_SEALED application, potentially undermining memory protection guarantees.

Classification
Working Poc 100%
Attack Type
Lpe
Complexity
Moderate
Reliability
Reliable
Target: Linux kernel 6.17-7.0-rc5
No auth needed
Prerequisites: Linux kernel with CONFIG_DEBUG_VM for visible warnings · Unprivileged user access
mistral-large-3 · analyzed May 02, 2026 Full analysis →
github WORKING POC
by TreasureBoy520 · pythonpoc
https://github.com/TreasureBoy520/cve-2026-poc-collection/tree/main/linux/CVE-2026-23416-POC

This PoC exploits a vulnerability in the Linux kernel's `mseal` syscall (CVE-2026-23416) where improper VMA (Virtual Memory Area) end tracking during VMA merges in `mseal_apply()` leads to a kernel warning (WARN_ON_VMG) in `vma_modify_flags()`. The exploit triggers a deterministic kernel warning by crafting overlapping memory mappings and sealing operations that expose the stale `curr_end` value issue.

Classification
Working Poc 99%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Linux kernel versions 6.17 through 7.0-rc5
No auth needed
Prerequisites: Linux kernel version between 6.17 and 7.0-rc5 · Unprivileged user access (no capabilities required) · Kernel compiled with `mseal` syscall support
mistral-large-3 · analyzed Aug 03, 2026 Full analysis →
github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/linux/CVE-2026-23416-POC

The repository contains a functional PoC for CVE-2026-23416, a Linux kernel vulnerability in the mm/mseal subsystem affecting versions 6.17 through 7.0-rc5. The exploit triggers a VM_WARN_ON_VMG assertion failure by manipulating VMA merging during mseal operations.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Linux kernel 6.17-7.0-rc5
No auth needed
Prerequisites: Unprivileged user access · Linux kernel 6.17-7.0-rc5
mistral-large-3 · analyzed May 21, 2026 Full analysis →
nomisec WORKING POC
by bluedragonsecurity · poc
https://github.com/bluedragonsecurity/CVE-2026-23416-POC

This repository contains a functional proof-of-concept exploit for CVE-2026-23416, a vulnerability in the Linux kernel's mm/mseal subsystem affecting versions 6.17 through 7.0-rc5. The exploit demonstrates a logic error in mseal_apply() where stale VMA end values lead to incorrect VM_SEALED application, potentially undermining memory protection guarantees.

Classification
Working Poc 100%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: Linux kernel 6.17-7.0-rc5
No auth needed
Prerequisites: Linux kernel 6.17-7.0-rc5 · CONFIG_DEBUG_VM for visible warning (optional)
mistral-large-3 · analyzed Apr 07, 2026 Full analysis →

Scores

CVSS v3 5.5
EPSS 0.0022
EPSS Percentile 12.3%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

Status published
Products (14)
linux/Kernel 6.17.0 - 6.18.21linux
linux/Kernel 6.19.0 - 6.19.11linux
Linux/Linux < 6.17
Linux/Linux 6.17
Linux/Linux 6.18.21 - 6.18.*
Linux/Linux 6.19.11 - 6.19.*
Linux/Linux 6c2da14ae1e0a0146587381594559027bd46c059 - 2697dd8ae721db4f6a53d4f4cbd438212a80f8dc
Linux/Linux 6c2da14ae1e0a0146587381594559027bd46c059 - 40b3f4700e5535fbe74738cebb9379a40ec66bed
Linux/Linux 6c2da14ae1e0a0146587381594559027bd46c059 - 83737e34b83a23b2a9bcf586b058b2c2a54c7c6b
Linux/Linux 7.0
... and 4 more
Published Apr 02, 2026
Tracked Since Apr 02, 2026