CVE-2023-26253: Gluster GlusterFS Buffer Overflow Flaw

CVE-2023-26253 Overview

CVE-2023-26253 is a stack-based buffer over-read vulnerability affecting Gluster GlusterFS 11.0. The flaw exists in the xlators/mount/fuse/src/fuse-bridge.c notify function, where improper bounds checking allows an attacker to read beyond the allocated buffer boundaries. This out-of-bounds read vulnerability can be exploited remotely without authentication, potentially leading to denial of service conditions on affected GlusterFS deployments.

Critical Impact
This vulnerability allows remote attackers to cause denial of service by triggering stack-based buffer over-read conditions in the FUSE bridge component, potentially disrupting distributed storage operations across enterprise environments.

Affected Products

Gluster GlusterFS 11.0
Systems running GlusterFS with FUSE mount enabled
Fedora distributions with vulnerable GlusterFS packages

Discovery Timeline

2023-02-21 - CVE-2023-26253 published to NVD
2025-03-14 - Last updated in NVD database

Technical Details for CVE-2023-26253

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-bounds Read), occurring within the FUSE bridge translator component of GlusterFS. The FUSE bridge serves as the critical interface between the kernel's FUSE module and GlusterFS userspace operations, handling filesystem notifications and requests.

The vulnerability manifests in the notify function within fuse-bridge.c, where insufficient validation of buffer boundaries during notification processing can result in reading memory beyond the allocated stack buffer. When exploited, this allows an attacker to trigger memory access violations, leading to service crashes and denial of service conditions.

The network attack vector with low complexity means exploitation can occur remotely without requiring authentication or user interaction, making this particularly concerning for internet-exposed GlusterFS deployments.

Root Cause

The root cause lies in improper bounds checking within the notification handling code path of the FUSE bridge translator. When processing certain notification events, the code fails to adequately verify that read operations remain within the bounds of the stack-allocated buffer. This oversight allows read operations to extend past the buffer's allocated memory region.

The fuse-bridge.c component acts as the translator layer between FUSE kernel requests and GlusterFS operations. When malformed or specially crafted requests reach the notify handler, the missing boundary validation allows the over-read condition to manifest.

Attack Vector

The attack can be executed remotely over the network without requiring any privileges or user interaction. An attacker with network access to a vulnerable GlusterFS service can send specially crafted requests that trigger the notify function's vulnerable code path. The exploitation results in reading stack memory beyond intended boundaries, which can cause the service to crash or become unresponsive.

The attack does not compromise data confidentiality or integrity directly, but the availability impact is significant as it can disrupt distributed storage services that enterprises depend on for critical operations.

Detection Methods for CVE-2023-26253

Indicators of Compromise

Unexpected crashes or restarts of GlusterFS daemon processes (glusterd, glusterfsd)
Segmentation fault errors in system logs related to GlusterFS FUSE operations
Abnormal memory access patterns or core dumps from GlusterFS processes

Detection Strategies

Monitor GlusterFS service logs for segmentation faults or memory access violations in fuse-bridge.c related functions
Implement network monitoring to detect unusual traffic patterns targeting GlusterFS ports (default 24007, 24008)
Deploy endpoint detection solutions capable of identifying process crashes associated with buffer over-read conditions

Monitoring Recommendations

Configure alerting on GlusterFS daemon unexpected terminations or restarts
Implement log aggregation to centralize GlusterFS service logs for anomaly detection
Monitor system stability metrics for storage nodes running GlusterFS 11.0

How to Mitigate CVE-2023-26253

Immediate Actions Required

Inventory all systems running GlusterFS 11.0 and prioritize them for patching
Review network exposure of GlusterFS services and restrict access to trusted networks where possible
Enable enhanced logging on GlusterFS services to detect potential exploitation attempts

Patch Information

Affected users should consult the GitHub Issue #3954 for the latest patch information and fixed versions. Fedora users should apply updates from the Fedora Package Announcement which addresses this vulnerability.

Administrators should update to the latest GlusterFS version that includes the security fix for the fuse-bridge.c notify function.

Workarounds

Restrict network access to GlusterFS services using firewall rules to limit exposure to trusted clients only
Consider temporarily disabling FUSE-based mounts if alternative access methods are available
Implement network segmentation to isolate GlusterFS infrastructure from untrusted network segments

bash

# Example: Restrict GlusterFS access to trusted network using firewalld
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="10.0.0.0/8" port port="24007-24008" protocol="tcp" accept'
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" port port="24007-24008" protocol="tcp" drop'
firewall-cmd --reload