CVE-2026-129490
Received Received - Intake

Type Confusion in LittleFS During Migration Process

Publication date: 2026-11-15

Last updated on: 2026-11-15

Assigner: VulnCheck

Description
littlefs through 2.11.3, when built with LFS_MIGRATE, contains a type confusion vulnerability in lfs_dir_traverse() that treats a stack lfs_diskoff struct as an lfs_attr array. Attackers can supply a crafted littlefs v1 image whose metadata is read as LFS_FROM_USERATTRS during migration, causing out-of-bounds stack reads and process crashes.

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Meta Information

Published
2026-11-15
Last Modified
2026-11-15
Generated
2026-11-15
AI Q&A
2026-11-15
EPSS Evaluated
N/A
NVD
CVE-2026-129490
EUVD
EUVD-2026-126101

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
littlefs-project littlefs From 0 (inc) to 2.11.3 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-843 The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

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Executive Summary

This vulnerability is a type confusion issue in the littlefs filesystem library (versions up to 2.11.3) when built with LFS_MIGRATE enabled. During migration operations, the lfs_dir_traverse() function incorrectly treats a stack-allocated lfs_diskoff struct as an lfs_attr array. Attackers can exploit this by providing a crafted littlefs v1 image with metadata interpreted as LFS_FROM_USERATTRS, causing out-of-bounds stack reads and process crashes.

Detection Guidance

Detecting this vulnerability requires analyzing littlefs filesystem images for malicious metadata. Use the provided PoC files from Resource 1 and Resource 2 to test systems. Compile and run fuzz_migrate.c against target littlefs v1 images to check for crashes or stack-buffer-overflows in sanitized builds.

Impact Analysis

This vulnerability allows attackers to crash applications processing untrusted littlefs v1 images via lfs_migrate(), causing denial-of-service conditions. In non-sanitized builds, it may lead to SIGSEGV crashes. Sanitized builds detect the issue earlier as a stack-buffer-overflow.

Compliance Impact

This vulnerability primarily causes denial-of-service conditions by crashing applications processing malicious littlefs v1 images. It does not directly expose or leak data, but crashes could disrupt systems handling sensitive data, potentially violating availability requirements in GDPR or HIPAA. However, no evidence suggests this vulnerability leads to data breaches or unauthorized access.

Mitigation Strategies

Disable LFS_MIGRATE in littlefs builds if not required. Update to a patched version once available. Validate filesystem images from untrusted sources before processing. Monitor applications using littlefs for crashes or SIGSEGV errors during migration operations.

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