Quick answers
- Is CVE-2026-48095 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-48095 being exploited in the wild.
- How severe is CVE-2026-48095?
- High severity, with a CVSS score of 8.8, published 5 June 2026.
- Which products and versions are affected?
- Igor Pavlov 7-Zip 26.00 and prior.
- Is there a fix for CVE-2026-48095?
- A patch was published on 2026-04-27: Version 26.01 released with fix. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-48095 attacked?
- It is attacked over the network or with local access, in a software library.
- Am I affected by CVE-2026-48095?
- Check whether anything you run is named in the advisory. 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 heap buffer overflow exists in the NTFS archive handler of 7-Zip (7z.dll). The root cause is an undefined behavior (UB) during a 32-bit left-shift operation in CInStream::GetCuSize(), where a crafted NTFS image with specific ClusterSizeLog and CompressionUnit values results in a 1-byte allocation for _inBuf. Subsequent calls to ReadStream_FALSE write up to 256 MB of attacker-controlled data into this 1-byte buffer. This leads to a vtable hijack of the CInStream object, which is located near the buffer on the heap. The vulnerability is reachable regardless of file extension due to 7-Zip's signature-based fallback mechanism. Fixed in version 26.01.
Affected products
- Igor Pavlov 7-Zip 26.00 and prior
Timeline
- 2026-04-24: disclosed: Reported to vendor via SourceForge private issue.
- 2026-04-27: patched: Version 26.01 released with fix.
- 2026-06-05: advisory: CVE-2026-48095 published.