CVE-2026-39891

# Proof of Concept for CVE-2026-39891 # This demonstrates how unescaped input leads to SSTI in PraisonAI < 4.5.115 # Assume we are interacting with the vulnerable agent API endpoint # The vulnerability is triggered when user input reaches 'acp_create_file' # which uses template rendering. malicious_payload = "{{ 7*7 }}" # Basic SSTI test payload # In a real scenario, this input would be sent to the agent.start() method # Example exploit flow: # 1. Attacker sends payload to agent.start() # 2. Input is passed to acp_create_file without escaping # 3. Template engine processes {{ 7*7 }} and returns "49" print(f"Sending payload to trigger template rendering: {malicious_payload}") print("If the application returns '49' instead of the literal string, it is vulnerable.")

{"cve": {"id": "CVE-2026-39891", "sourceIdentifier": "[email protected]", "published": "2026-04-08T21:17:01.403", "lastModified": "2026-04-22T16:51:30.870", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "PraisonAI is a multi-agent teams system. Prior to 4.5.115, the create_agent_centric_tools() function returns tools (like acp_create_file) that process file content using template rendering. When user input from agent.start() is passed directly into these tools without escaping, template expressions in the input are executed rather than treated as literal text. This vulnerability is fixed in 4.5.115."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-94"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*", "versionEndIncluding": "4.5.114", "matchCriteriaId": "B0754891-B47D-441D-A0E6-710A49389AE4"}]}]}], "references": [{"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-hwg5-x759-7wjg", "source": "[email protected]", "tags": ["Vendor Advisory", "Exploit"]}, {"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-hwg5-x759-7wjg", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Vendor Advisory", "Exploit"]}]}}