CVE-2026-61439 Overview
CVE-2026-61439 affects PraisonAI versions before 4.6.78. The framework ships with a prompt injection defense misconfiguration where the block threshold defaults to CRITICAL severity. This default allows HIGH-severity threats to pass through the filter without being blocked. Attackers can submit single-vector prompt injection payloads such as instruction overrides or financial manipulation prompts. These payloads trigger HIGH severity detection but are only logged, never blocked. Successful exploitation enables system prompt extraction and unauthorized tool invocations against the underlying agent. The weakness is tracked under CWE-1188 (initialization of a resource with an insecure default).
Critical Impact
Unauthenticated network attackers can bypass PraisonAI's prompt injection defense to extract system prompts and invoke agent tools without authorization.
Affected Products
- PraisonAI versions prior to 4.6.78
- Deployments relying on the default prompt injection block threshold
- Agentic workflows exposing tool invocation to untrusted input
Discovery Timeline
- 2026-07-11 - CVE-2026-61439 published to NVD
- 2026-07-14 - Last updated in NVD database
Technical Details for CVE-2026-61439
Vulnerability Analysis
PraisonAI includes a layered prompt injection defense that classifies incoming prompts by severity. The defense supports thresholds such as LOW, MEDIUM, HIGH, and CRITICAL. Only inputs at or above the configured threshold are blocked. Because the default threshold is set to CRITICAL, inputs classified as HIGH are logged as detections but forwarded to the model unchanged. This creates a gap between detection and enforcement in default deployments.
Attackers exploit this gap using single-vector payloads that the classifier scores as HIGH rather than CRITICAL. Typical vectors include direct instruction overrides that redirect the agent's behavior and financial manipulation prompts that alter tool parameters. Because the payload reaches the model, attackers can retrieve the system prompt and trigger tool calls outside the agent's intended scope. The issue affects confidentiality of the agent's configuration and integrity of downstream tool operations.
Root Cause
The root cause is an insecure default configuration [CWE-1188]. The block threshold is initialized to CRITICAL, which excludes HIGH-severity classifications from enforcement. Operators who accept defaults inherit a permissive policy that logs rather than blocks known-malicious prompts.
Attack Vector
Exploitation occurs over the network without authentication or user interaction. An attacker submits a crafted prompt to any PraisonAI endpoint that forwards user input to the agent. The prompt is scored HIGH, logged, and passed to the model. The attacker then reads the system prompt from the response or observes side effects of unauthorized tool invocations. Refer to the GitHub Security Advisory GHSA-fj8f-m44g-c479 and the VulnCheck Advisory for technical details.
Detection Methods for CVE-2026-61439
Indicators of Compromise
- Log entries showing prompt injection detections at HIGH severity that were not blocked
- Agent responses containing verbatim system prompt content or role definitions
- Tool invocations with parameters that do not match the originating user request
- Repeated prompts containing instruction-override phrases such as "ignore previous instructions" or role reassignment directives
Detection Strategies
- Alert on any PraisonAI log event where injection severity equals HIGH and the action is log rather than block
- Correlate detected injection events with subsequent tool invocation logs within the same session
- Baseline expected tool call patterns per agent and flag deviations tied to user-supplied input
Monitoring Recommendations
- Forward PraisonAI application logs and agent tool audit logs to a centralized analytics platform for correlation
- Monitor outbound tool calls, especially those with financial, file system, or network side effects
- Track PraisonAI package versions across environments and alert on any host running a version earlier than 4.6.78
How to Mitigate CVE-2026-61439
Immediate Actions Required
- Upgrade PraisonAI to version 4.6.78 or later on all deployments
- Explicitly set the prompt injection block threshold to HIGH or lower until upgrades complete
- Review recent agent logs for HIGH-severity detections and investigate any associated tool invocations
- Rotate any secrets, API keys, or credentials referenced in agent system prompts that may have been exposed
Patch Information
The fix is available in PraisonAI 4.6.78. Consult the GitHub Security Advisory GHSA-fj8f-m44g-c479 for release notes and configuration guidance.
Workarounds
- Configure the prompt injection defense threshold to block at HIGH severity in application configuration
- Restrict which tools the agent can invoke and require explicit allow-lists for sensitive actions
- Place PraisonAI endpoints behind an authenticated gateway to limit exposure to untrusted input
# Configuration example: lower the block threshold to HIGH
export PRAISONAI_INJECTION_BLOCK_THRESHOLD=HIGH
pip install --upgrade "praisonai>=4.6.78"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
