CVE-2026-99091

NONE
Published: 2026-10-26
Modified: 2026-10-26
Enriched via mock
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AI Threat Summary

CVE-2026-99091 is a moderate vulnerability affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: Fix status of pending commands flushed on power off cmd_complete_rsp() receives a struct cmd_lookup and, for a pending command that has no cmd_complete callback, falls through to cmd_status_rsp(cmd, data). cmd_status_rsp() reads data as a u8 *, so the status sent comes from the first byte of match->sk's representation, not from match->mgmt_status. commit f53e1c9c726d ("Bluetooth: MGMT: Fix possible crash on mgmt_index_removed") changed the callers' data from &status to &match and updated the cmd_complete branch to match->mgmt_status, but left the fall-through passing data unchanged. In mgmt_index_removed() match->sk is NULL, so every such command is answered with status 0x00 (Success) instead of MGMT_STATUS_INVALID_INDEX. In __mgmt_power_off() it is NULL too, unless a Set Powered command was pending: then settings_rsp() has stored that command's socket in match->sk, and the byte sent comes from the socket pointer. Either way the status the caller set, MGMT_STATUS_NOT_POWERED (or MGMT_STATUS_INVALID_INDEX when the device is being unregistered), is lost. Pass the status the callers set. This was seen on a QCA9377 laptop: bluetoothd's Start Discovery, pending when the adapter was powered off, was answered with Command Status 0x00 and no parameters, and bluetoothd 5.72 crashed on the zero-length success. BlueZ master has since added the length check on that path ("adapter: Fix crash on short start discovery reply", BlueZ a734b06059cb), but userspace should still be told Not Powered, not Success. Tested on Ubuntu 7.0.0-31 with a virtual controller (hci_vhci): power off is held in HCI Write Scan Enable while a Start Discovery is submitted, and the flush answers it with status 0x00 before this change and 0x0f (Not Powered) after.

Attack Chain
1
Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

2
Initial Access

Attacker triggers CVE-2026-99091 vulnerability with a crafted request or payload

3
Execution

Vulnerability exploited to perform unauthorized actions on the target system

4
Impact

Depending on vulnerability type, attacker achieves data access, service disruption, or code execution

MITRE ATT&CK Techniques
T1190 Exploit Public-Facing Application
Initial Access

Public-facing application vulnerability exploited for initial access

T1203 Exploitation for Client Execution
Execution

Vulnerability exploited to execute attacker-controlled code

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2026-99091
CVSS Score N/A
Published 2026-10-26
Exploited No
CISA KEV No
PoC Not public
References
External Resources
NVD Entry BleepingComputer The Hacker News