An out-of-bounds read in the ext4_ext_binsearch_idx function in src/ext4_extent.c of the…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2025-70101
- 2026-10-03 Alias added: GHSA-4v99-r46p-gx3v
References
More Gkostka Lwext4 vulnerabilities
- TI-2025-43031 A divide-by-zero vulnerability in the ext4_block_set_lb_size function in… CVSS 3.1MEDIUM 5.5
Sources
- CVE-2025-70101 · CVE Program
- CVE-2025-70101 · NVD
- FIRST EPSS
- GHSA-4v99-r46p-gx3v · GitHub Advisory Database · CC BY 4.0
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