CVE-2026-99051

HIGH CVSS 7.8 PoC Available
Published: 2026-10-23
Modified: 2026-10-24
Enriched via mock
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AI Threat Summary

CVE-2026-99051 is a high-severity vulnerability with a CVSS score of 7.8 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: fsverity: RCU-delay the freeing of struct fsverity_info __fsverity_get_info() calls rhashtable_lookup_fast(), which just uses rcu_read_lock() and doesn't directly synchronize with fsverity_remove_info(). For the same inode this isn't a problem: its fsverity_info is removed only at inode eviction time or upon failure to enable verity, when the inode no longer needs its fsverity_info and it will no longer be accessed via that inode. However, this is broken and can cause a use-after-free for concurrent __fsverity_get_info() for *different* inodes. Those rely on following fsverity_info::rhash_head in the rhashtable under rcu_read_lock() only. They also use fsverity_info::inode to do the key comparison. Fix this by RCU-delaying the freeing of 'struct fsverity_info' after it's been removed from the rhashtable.

Attack Chain
1
Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

2
Initial Access

Attacker triggers CVE-2026-99051 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-2026-99051
CVSS Score 7.8
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published 2026-10-23
Exploited No
CISA KEV No
PoC Available
References
External Resources
NVD Entry BleepingComputer The Hacker News