CVE-2026-22258 Overview
CVE-2026-22258 is a resource exhaustion vulnerability affecting Suricata, a widely-deployed open-source network IDS, IPS, and NSM (Network Security Monitoring) engine. The vulnerability exists in the DCERPC (Distributed Computing Environment / Remote Procedure Call) protocol parser, where specially crafted traffic can cause Suricata to expand a buffer without limits. This unbounded memory allocation leads to memory exhaustion and ultimately causes the Suricata process to be killed by the operating system.
While the vulnerability was initially reported for DCERPC over UDP, it is believed that DCERPC over TCP and DCERPC over SMB are also vulnerable. The default configuration for DCERPC/TCP provides some inherent protection as the stream depth is limited to 1MiB. However, DCERPC/SMB configurations using unlimited stream.reassembly.depth remain fully vulnerable.
Critical Impact
Attackers can remotely crash Suricata network security engines through crafted DCERPC traffic, potentially creating security monitoring blind spots in enterprise networks during incident response scenarios.
Affected Products
- Suricata versions prior to 8.0.3
- Suricata versions prior to 7.0.14
- Installations with DCERPC/SMB using unlimited stream.reassembly.depth
Discovery Timeline
- 2026-01-27 - CVE CVE-2026-22258 published to NVD
- 2026-01-29 - Last updated in NVD database
Technical Details for CVE-2026-22258
Vulnerability Analysis
This vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption). The flaw resides in Suricata's DCERPC protocol parser which fails to implement proper bounds checking when expanding internal buffers during traffic reassembly. When processing malformed or specifically crafted DCERPC packets, the parser allocates increasingly large amounts of memory without enforcing any upper limits.
The attack can be initiated remotely over the network without authentication, making it particularly dangerous for organizations relying on Suricata for network security monitoring. Successful exploitation results in complete denial of service of the Suricata engine, which may leave network traffic unmonitored and potentially allow other malicious activities to proceed undetected.
Root Cause
The root cause is improper resource consumption controls in the DCERPC parser's buffer expansion logic. When reassembling fragmented DCERPC traffic, the parser dynamically allocates memory to accommodate incoming data. The absence of maximum allocation limits allows an attacker to trigger unbounded memory growth by sending a continuous stream of crafted packets, eventually exhausting all available system memory.
Attack Vector
The vulnerability is exploitable via network-based attacks targeting DCERPC protocol traffic. An attacker can send crafted DCERPC packets over three potential transport mechanisms:
- DCERPC/UDP: Directly vulnerable; no configuration-based protection available
- DCERPC/TCP: Protected by default 1MiB stream depth limit, but custom configurations may remove this protection
- DCERPC/SMB: Vulnerable when stream.reassembly.depth is set to unlimited (the default configuration)
The attack requires no authentication and no user interaction, allowing adversaries to remotely trigger memory exhaustion against any exposed Suricata instance processing DCERPC traffic.
The exploitation mechanism involves sending malformed DCERPC traffic that triggers the parser to continuously expand its internal buffer. As documented in the GitHub Security Advisory, the lack of bounds checking allows memory consumption to grow unbounded until the system's OOM (Out of Memory) killer terminates the Suricata process.
Detection Methods for CVE-2026-22258
Indicators of Compromise
- Suricata process unexpectedly terminated or restarted
- Sudden memory usage spikes on systems running Suricata
- OOM killer entries in system logs referencing Suricata process
- Gaps in network traffic monitoring logs coinciding with memory exhaustion events
- Unusual volume of DCERPC traffic from external sources
Detection Strategies
- Monitor system memory utilization for Suricata processes and alert on abnormal growth patterns
- Configure process monitoring to detect unexpected Suricata terminations or restarts
- Review system logs for OOM killer activity targeting Suricata
- Implement network traffic analysis to identify anomalous DCERPC packet patterns
Monitoring Recommendations
- Deploy memory usage alerting thresholds specific to Suricata instances
- Enable centralized logging for Suricata process health and system resource metrics
- Correlate network monitoring gaps with potential exploitation attempts
- Establish baseline DCERPC traffic volumes to detect statistical anomalies
How to Mitigate CVE-2026-22258
Immediate Actions Required
- Upgrade Suricata to version 8.0.3 or 7.0.14 immediately
- Review current Suricata configurations for DCERPC parser settings
- Assess exposure of Suricata instances to untrusted network traffic
- Implement the workarounds below if immediate patching is not feasible
Patch Information
The OISF (Open Information Security Foundation) has released patches in Suricata versions 8.0.3 and 7.0.14 that address this vulnerability. The fixes implement proper bounds checking in the DCERPC parser to prevent unbounded buffer expansion.
Relevant patch commits are available at:
For additional details, refer to the OISF issue tracker and the GitHub Security Advisory.
Workarounds
- For DCERPC/UDP: Disable the DCERPC/UDP parser entirely to eliminate the attack surface
- For DCERPC/TCP: Configure stream.reassembly.depth to enforce a memory limit (default 1MiB provides protection)
- For DCERPC/SMB: Set stream.reassembly.depth to a bounded value, noting this may impact SMB visibility
- Implement network-level filtering to limit DCERPC traffic from untrusted sources
- Consider rate-limiting DCERPC connections at the network perimeter
# Suricata configuration workaround example
# Limit stream reassembly depth to prevent memory exhaustion
stream:
reassembly:
depth: 1mb # Set explicit limit for TCP reassembly
# Note: May reduce visibility for SMB traffic analysis
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
