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CVE-2026-26932 is a vulnerability in Elastic’s Packetbeat network data shipper, stemming from improper validation of array indices (CWE-129) within its PostgreSQL protocol parser. Packetbeat is designed to capture and dissect network traffic, including PostgreSQL database traffic, to monitor application performance. The flaw lies in how the parser handles specially crafted packets that manipulate input data. When Packetbeat, with the ‘pgsql’ protocol explicitly enabled in its configuration, processes a malicious packet, an invalid array index is accessed. In Go, this type of memory access violation is not handled gracefully; instead, it triggers a runtime panic. A panic in Go is an unexpected condition that causes the program to crash and terminate, rather than continuing to operate. Consequently, an attacker who can send network traffic to a port monitored by a vulnerable Packetbeat instance can cause the process to shut down reliably. This leads to a Denial of Service (DoS) as the monitoring agent stops functioning, disrupting log ingestion and network visibility. The attack requires the target to have PostgreSQL protocol decoding active, meaning the vulnerable component must be configured in a specific state. The CVSS score for this vulnerability is 5.7 (Medium), with a vector string of CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating a high availability impact from an adjacent network position .
dailycve form:
Platform: Elastic Packetbeat
Version: 8.0.0-8.19.10, 9.0.0-9.2.4
Vulnerability :Array index validation
Severity: Medium (5.7)
date: February 26, 2026
Prediction: Patch by March 2026
What Undercode Say:
Analytics:
Check Packetbeat version
sudo packetbeat version
Check if pgsql protocol is enabled in config
grep 'pgsql' /etc/packetbeat/packetbeat.yml
Test for vulnerable configuration
sudo packetbeat test config
Simulate detection of malicious packets (Conceptual)
sudo tcpdump -i any -A 'port 5432' | grep -i "malformed"
Count Packetbeat crashes in logs
journalctl -u packetbeat --since "2026-02-26" | grep -c "panic"
Monitor for process restarts
systemctl status packetbeat | grep "Active:"
Check for CVE patch version (Fixed in 8.19.11 / 9.2.5)
dpkg -l | grep packetbeat | grep -E "8.19.11|9.2.5"
List network interfaces Packetbeat is monitoring
sudo packetbeat devices
Check open file descriptors for Packetbeat
lsof -p $(pgrep packetbeat) | wc -l
Monitor Packetbeat memory usage
ps aux | grep packetbeat | awk '{print $4, $11}'
Search for recent security updates
apt-cache policy packetbeat | grep Candidate
Examine Go runtime logs for panics
journalctl -u packetbeat | grep -i "panic" -A 10
How Exploit:
An attacker, positioned on an adjacent network, sends a specially crafted packet to a port monitored by a vulnerable Packetbeat instance where the ‘pgsql’ protocol is enabled. The packet exploits the improper array index validation in the PostgreSQL protocol parser. When processed, this triggers an unhandled Go runtime panic, causing the Packetbeat process to terminate immediately. This results in a Denial of Service as the network monitoring agent stops working. No public exploit is currently available .
Protection from this CVE:
- Patch Immediately: Update Packetbeat to versions 8.19.11, 9.2.5, or later .
- Disable Unused Protocols: If PostgreSQL monitoring is not required, disable the ‘pgsql’ protocol in
packetbeat.yml. - Network Segmentation: Restrict network access to the monitored ports from untrusted adjacent networks.
- Monitoring: Set up alerts for unexpected process terminations or crashes of the Packetbeat service.
Impact:
A successful exploit results in a complete Denial of Service of the Packetbeat instance. This halts the collection and shipping of network metrics, creating a blind spot in application and infrastructure monitoring. It prevents visibility into network transactions, hinders troubleshooting, and can break automated alerting systems that rely on this data. The availability of the monitoring service is entirely compromised until the process is manually restarted or automatically respawned, though the crash can be repeated .
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Sources:
Reported By: nvd.nist.gov
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