CVE-2020-25578

MEDIUM

FreeBSD <12.2-STABLE r368969, 11.4-STABLE r369047, 12.2-RELEASE p3,...

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2020-25578. PoCs published by farazsth98.

AI-analyzed exploit summary This repository contains proof-of-concept code for CVE-2020-25578, an information leak vulnerability in FreeBSD's filesystem implementations. The PoCs demonstrate how uninitialized padding bytes in `struct dirent` can leak kernel memory, including pointers, due to incomplete patches in functions like `msdosfs_readdir` and variants in other filesystems.

Description

In FreeBSD 12.2-STABLE before r368969, 11.4-STABLE before r369047, 12.2-RELEASE before p3, 12.1-RELEASE before p13 and 11.4-RELEASE before p7 several file systems were not properly initializing the d_off field of the dirent structures returned by VOP_READDIR. In particular, tmpfs(5), smbfs(5), autofs(5) and mqueuefs(5) were failing to do so. As a result, eight uninitialized kernel stack bytes may be leaked to userspace by these file systems.

Exploits (1)

nomisec WORKING POC 6 stars
by farazsth98 · poc
https://github.com/farazsth98/freebsd-dirent-info-leak-bugs

This repository contains proof-of-concept code for CVE-2020-25578, an information leak vulnerability in FreeBSD's filesystem implementations. The PoCs demonstrate how uninitialized padding bytes in `struct dirent` can leak kernel memory, including pointers, due to incomplete patches in functions like `msdosfs_readdir` and variants in other filesystems.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: FreeBSD (multiple versions, including those with msdosfs, mqueuefs, tmpfs, smbfs, or autofs)
No auth needed
Prerequisites: Access to a FreeBSD system with vulnerable filesystems mounted · Ability to compile and execute C code on the target system
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (2)

Core 2
Core References
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20210423-0002/

Scores

CVSS v3 5.3
EPSS 0.0232
EPSS Percentile 81.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Details

CWE
CWE-665
Status published
Products (3)
freebsd/freebsd 11.4 (7 CPE variants)
freebsd/freebsd 12.1 (13 CPE variants)
freebsd/freebsd 12.2 (3 CPE variants)
Published Mar 26, 2021
Tracked Since Feb 18, 2026