Vulnerability Summary
- Identifier: CVE-2026-24343
- Product Affected: Apache HertzBeat
- Type of Vulnerability: XPath Injection
- Severity: High
- CVSS Score: 8.8
- Exploit Availability: No confirmed exploit released publicly
- Official Patch / Upgrade:
🔗 https://hertzbeat.apache.org/docs/download/
This vulnerability exists because Apache HertzBeat versions prior to the patched release do not properly validate or neutralize user-supplied input before using it to build XPath queries against internal XML data. When input is taken directly from a request and placed into an XPath expression, it creates an opportunity for manipulation.
Technical Impact
XPath Injection allows an attacker to modify the logic of an XPath query by inserting special characters or expressions. In the context of HertzBeat:
- User input is taken from web API parameters or data payloads.
- That input is used inside an XPath evaluation routine without sufficient validation.
- An attacker who can send crafted input to those endpoints can manipulate the structure of the XPath expression.
This can lead to two classes of impact:
- Unauthorized Data Disclosure
By altering the XPath query, an attacker can cause the application to return nodes or values it was not intended to return. This can expose configuration, metric details, internal identifiers, or other sensitive data. - Resource Exhaustion / Service Disruption
Carefully crafted XPath expressions can force the processing engine into heavy recursive evaluation. This can consume CPU and memory, slowing the application or causing it to become unavailable.
Because the affected endpoints are reachable over the network, and the vulnerability does not require administrative privileges, it is considered high risk.
How an Attack Might Work (Educational)
To understand how someone could misuse this weakness for testing or education:
- A request is sent to an HTTP API endpoint where HertzBeat accepts some form of parameter or input that influences data selection.
- Instead of submitting normal values, an attacker sends input containing special XPath operator sequences or function names.
- The application inserts that input into an XPath query without strict validation.
- The XPath query behaves differently than intended:
- It may evaluate additional branches of the XML data tree.
- It may require significantly more computational work to evaluate.
Successful manipulation leads to either sensitive data being returned or the service slowing down or failing.
No public proof-of-concept is widely available, so attackers would need to discover the exact injection points and input schemes themselves. This means defenders can stay ahead by monitoring for textbook injection indicators.
Detection Strategy
Detecting attempts to misapply this vulnerability in real traffic requires focusing on the inputs, errors, performance spikes, and unexpected query behavior.
Good detection is built on three pillars:
- Monitoring Incoming Request Patterns
- Inspecting Application-Level Errors and Exceptions
- Observing System Performance Anomalies
Each of these can provide early warning before a real breach occurs.
1. Detecting Suspicious Inputs
Regardless of exploit code, injection attempts involve patterns that wouldn’t normally appear in legitimate requests. These include XPath operators, function names, or unusual sequences.
Here are sample queries to help detect abnormal request payloads in your logs.
Web Access Log Pattern Detection
(index=web_logs) (uri="/collector" OR uri="/api/") AND
(
query_statement IN ("concat(", "substring(", "position(", "name(", "text(")
OR url_param_matches_regex="(\/\/|@\w+|\bor\b|\band\b)"
)
| stats count as attack_attempts by client_ip, uri
| where attack_attempts > 3
This rule looks for:
- Repeated requests to HertzBeat API paths.
- Parameters that include XPath operators or function names.
- Grouping by the source IP to correlate potential scanning/probing.
You can adapt field names to match your logging format.
2. Identifying Application Exceptions
When an application receives malformed input and cannot parse it correctly, it may log internal errors. Even if the vulnerability is not fully exploited, parsing and evaluation errors increase.
General Application Log Diagnostic Query
(index=app_logs) ("XPath" OR "XML" OR "expression")
| stats count as error_count by host, log_message
| where error_count > 5
This query helps you find unusual patterns in logs where the application indicated parsing or expression evaluation issues. Elevated counts from a particular host or time window should prompt investigation.
3. Performance Anomaly Detection
If the service begins consuming more CPU or memory than usual, that spike could correlate with malicious input causing expensive evaluation.
Resource Monitoring Alert Rule
alert if
average(cpu_percent) > 70% for 5 minutes
AND
sum(http_requests to "/collector") > baseline_threshold
This sort of alert looks for sustained resource usage above normal levels along with unusual request volumes.
Pair this with fine-grained logging to correlate spikes with certain patterns in request payloads.
Logging Recommendations
To detect misuse effectively, collect the following for each request:
- Client IP
- User identity (if authenticated)
- Full request URI and query parameters
- Request body (where it is safe to log)
- Timestamp with timezone
- Response status code
- Application error details
- Latency and resource usage records
Be sure that your logging does not itself expose sensitive information, especially in request bodies — apply redaction where needed.
Log retention should meet your organization’s policy, but keep at least enough historical data to correlate spikes in behavior over days or weeks.
Remediation Guidance
The most effective mitigation for this vulnerability is to update all affected components to the patched version of the software.
➡️ Official Patch / Upgrade:
https://hertzbeat.apache.org/docs/download/
Steps to remediate:
- Identify All HertzBeat Instances
Check both servers and collectors for version information. - Plan Upgrade Rollout
Perform canary testing in a staging environment before full production rollout. - Verify Patch Integrity
Check checksums/signatures of the downloaded release. - Deploy with Monitoring
After upgrading, monitor your service closely for any errors or anomalies. - Review Access Policies
Restrict access to administrative or collector endpoints to trusted networks and authenticated users only.
Interim Hardening
If you cannot upgrade immediately, consider applying these temporary defenses:
- Web Application Firewall (WAF) rules that filter out suspicious input patterns before they reach the application.
- Network Access Control to limit who can connect to HertzBeat endpoints.
- Rate Limiting to reduce the effectiveness of brute-force injection attempts.
- Tighter Input Validation inside any custom integrations that talk to HertzBeat APIs.
These measures reduce exposure but do not replace the patch.
Educational Understanding of Exploitation
To responsibly defend against this class of vulnerability:
- Recognize that user input must always be treated as untrusted.
- Any system that evaluates expressions based on input should enforce strict validation or use parameterized APIs.
- Monitoring must focus on both structural anomalies in requests and their side effects on system behavior.
Understanding these principles lets teams write detection rules and alarms that catch attempts before they cause damage.
Checklist for SOC
Before closing out response actions:
- Inventory all HertzBeat components and versions
- Upgrade to patched release via official link
- Tune and deploy log detection patterns
- Implement resource monitoring alerts
- Harden network and access controls
- Review and test WAF filtering rules
