Is CVE-2025-70101 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-70101 being exploited in the wild.

How severe is CVE-2025-70101?

Informational severity, with a CVSS score of 5.5, published 3 June 2026.

Is there a fix for CVE-2025-70101?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2025-70101 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2025-70101?

Check whether you run Grzegorz Kostka Lwext4 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2025-70101: gkostka lwext4 out-of-bounds read in ext4_ext_binsearch_idx

CVE-2025-70101 · Severity: info · CVSS 5.5 · Published 2026-06-03

A vulnerability in the lwext4 library, which provides ext4 filesystem support for embedded systems, could allow an attacker to crash applications using the library. By providing a specially crafted or corrupted filesystem image, an attacker can trigger a memory error that leads to a denial of service. This could impact the availability of devices or software that automatically mount or read external storage media.

Technologies: Grzegorz Kostka Lwext4. Vendors: Grzegorz Kostka.

Quick answers

Is CVE-2025-70101 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-70101 being exploited in the wild.
How severe is CVE-2025-70101?: Informational severity, with a CVSS score of 5.5, published 3 June 2026.
Which products and versions are affected?: Grzegorz Kostka Lwext4 1.0.0.
Is there a fix for CVE-2025-70101?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2025-70101 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2025-70101?: Check whether you run Grzegorz Kostka Lwext4 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An out-of-bounds read exists in the ext4_ext_binsearch_idx function within src/ext4_extent.c of lwext4 1.0.0. The vulnerability is caused by insufficient validation of the extent header fields (specifically eh_entries and eh_depth) before performing a binary search over extent index entries. If a crafted filesystem image contains an internal node where eh_depth is greater than zero but eh_entries is zero, the EXT_FIRST_INDEX and EXT_LAST_INDEX macros return invalid pointers. This leads to invalid pointer calculations and a subsequent out-of-bounds memory read (segmentation fault) during extent tree traversal. Attackers can exploit this by providing a malicious filesystem image to be processed by the library.

Affected products

gkostka lwext4 1.0.0

Timeline

2025-12-09: disclosed: Issue reported on GitHub
2026-06-03: advisory: NVD published CVE-2025-70101

References

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