CVE-2025-70101

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-03 · updated 2026-07-22
Weakness: CWE-125

Description

An out-of-bounds read in the ext4_ext_binsearch_idx function in src/ext4_extent.c of the lwext4 1.0.0 library allows attackers to cause a denial of service by supplying a specially crafted ext4 filesystem image. The vulnerability occurs due to insufficient validation of extent header fields before performing a binary search over extent index entries, which can result in invalid pointer calculations and an out-of-bounds memory read during extent tree traversal.

Affected products

Gkostka Lwext4: 1.0.0

References

https://github.com/gkostka/lwext4/issues/91
https://github.com/sigdevel/pocs/blob/main/res/lwext4/3/sig11_lwext4_ext4_extent_815
https://infosec.exchange/@sigdevel/116668958927817708
http://www.openwall.com/lists/oss-security/2026/06/29/6
https://github.com/gkostka/lwext4/issues/91

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