Is CVE-2025-70099 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-70099 being exploited in the wild.

How severe is CVE-2025-70099?

Informational severity, with a CVSS score of 0, published 1 June 2026.

Is there a fix for CVE-2025-70099?

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-2025-70099 attacked?

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

Am I affected by CVE-2025-70099?

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-2025-70099: lwext4 NULL pointer dereference in ext4_dir_en_get_name_len

CVE-2025-70099 · Severity: info · CVSS 0 · Published 2026-06-01

lwext4 is a lightweight library used to provide EXT4 filesystem support for embedded systems and small devices. A vulnerability in how the library handles directory information could allow a malicious actor to crash a system by providing a specially crafted, corrupted filesystem image. This results in a denial of service, potentially causing devices to reboot or stop functioning when they attempt to read the malicious data.

Technologies: Grzegorz Kostka Lwext4. Vendors: Grzegorz Kostka.

Quick answers

Is CVE-2025-70099 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-70099 being exploited in the wild.
How severe is CVE-2025-70099?: Informational severity, with a CVSS score of 0, published 1 June 2026.
Which products and versions are affected?: Grzegorz Kostka Lwext4 1.0.0.
Is there a fix for CVE-2025-70099?: 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-2025-70099 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2025-70099?: 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

A NULL pointer dereference exists in the ext4_dir_en_get_name_len function within include/ext4_dir.h of lwext4 1.0.0. The vulnerability is triggered during directory iteration when the library processes a malformed EXT4 filesystem image containing corrupted directory entries. Specifically, the ext4_dir_entry_next function may pass an invalid or NULL directory entry pointer to ext4_dir_en_get_name_len, which attempts to access the name_len field without prior validation. This results in a segmentation fault and subsequent denial of service. The issue was identified via fuzzing and affects the 2016-era codebase (commit 58bcf89).

Affected products

gkostka lwext4 1.0.0

Timeline

2025-12-09: disclosed: Issue reported on GitHub repository
2026-06-01: advisory: CVE published to NVD

References

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