Quick answers
- Is CVE-2026-99273 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-99273 being exploited in the wild.
- How severe is CVE-2026-99273?
- Informational severity, published 7 November 2026.
- Which products and versions are affected?
- Linux Kernel versions prior to commit a025c4991a7d83edc4dd339e3ea86d8ff6226eca.
- Is there a fix for CVE-2026-99273?
- 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-2026-99273 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-99273?
- Check whether you run Linux Kernel 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
The get_file_stream_info() function in fs/smb/server/smb2pdu.c miscalculates buffer space required for SMB2 stream name responses. The smbConvertToUTF16() function always appends a two-byte UTF-16 null terminator, but the budget checks reserve space only for the converted characters. When a stream entry exactly fills the small response buffer, the terminator writes two bytes past the allocated heap, causing a heap buffer overflow. This is a local or network attack via SMB protocol requiring file access permissions.
Affected products
- Linux Linux kernel versions prior to commit a025c4991a7d83edc4dd339e3ea86d8ff6226eca
Timeline
- 2026-11-07: disclosed