Horizon Alert
Summary of the vulnerability and why it matters
This issue in the Linux kernel could allow an attacker to cause a system crash. It occurs when a specific, uncommon configuration setting is used, leading to a read outside of allocated memory.
- Can cause system instability.
- Affects systems with a specific configuration.
Attack Path
How an attacker could exploit the issue
An attacker would need local access to a Linux system and the ability to modify kernel boot parameters. By setting `dhash_entries=1`, they could trigger an out-of-bounds read in the kernel's dentry hash table, leading to a kernel crash.
- Requires local admin access.
- Target is kernel boot parameter.
- Causes kernel crash.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability involves an out-of-bounds read in the Linux kernel's dentry hash table, triggered by a specific, non-default kernel parameter. While this could lead to system instability or crashes, it requires an attacker to first gain administrative privileges or otherwise manipulate kernel boot parameters, making direct exploitation for widespread compromise unlikely. The complexity and prerequisites for triggering this flaw suggest it's more of a local privilege escalation or denial-of-service vector for an already compromised system rather than a remote exploit.
- Requires admin access to set parameter.
- No public exploit code known.
- No KEV listing.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Teams should prioritize identifying and isolating Linux systems where the `dhash_entries=1` kernel parameter may be configured, as this could lead to critical out-of-bounds read vulnerabilities. Focus on systems with known administrative access or those running specialized services that might utilize custom kernel parameters. Given the complexity of exploitation, containment through parameter modification is a strong mitigation.
- Block `dhash_entries=1` kernel parameter.
- Monitor systems for OOB read errors.
- Upgrade kernel to a fixed version.
