AZL-100694

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Import Source
https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100694.json
JSON Data
https://api.osv.dev/v1/vulns/AZL-100694
Upstream
Published
2026-09-11T20:19:49Z
Modified
2026-09-13T06:06:36Z
Summary
CVE-2026-89637 affecting package kernel 6.6.150.1-1
Details

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix UAF and buffer leak in cifs_check_trans2() for malformed secondary T2

When a valid primary TRANSACT2 response has been received (mid->resp_buf set, mid->multiRsp true) and a subsequent secondary response causes cifs_check_trans2() to return false -- either because the SMB header is invalid (malformed != 0) or because check2ndT2() rejects the PDU -- handle_mid() overwrites mid->resp_buf with the new buffer (leaking the primary buffer) and, because mid->multiRsp is set, skips the server->smallbuf/bigbuf NULL-out. When the user thread frees mid->resp_buf, server->smallbuf or server->bigbuf is left dangling; the demux thread reuses it for the next packet, resulting in a use-after-free.

Combine both early-exit conditions and, when mid->multiRsp is already set, abort the pending transaction inline: set multiEnd, call dequeue_mid() with malformed=true, and return true so handle_mid() exits without touching mid->resp_buf or the server buffer pointers.

References

Affected packages

Azure Linux:3 / kernel

Package

Name
kernel
Purl
pkg:rpm/azure-linux/kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Last Affected
6.6.150.1-1

Database specific

source
"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100694.json"