Code Injection in praisonai (CVE-2026-39891)
Summary
Code injection in praisonai (CVE-2026-39891). Successful exploitation can lead to full system takeover. Exploitable via acp_create_file. Mitigation: upgrade to 4.5.115 or later.
Original description
The description as published by the source.
Summary
Direct insertion of unescaped user input into template-rendering tools allows arbitrary code execution via specially crafted agent instructions.
Details
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 (as shown in agent_centric_example.py:85-86), template expressions in the input are executed rather than treated as literal text. This occurs because:
- No input sanitization or escaping is applied to user-controlled content
- The ACP-enabled runtime auto-approves operations (
approval_mode="auto") - Tools lack context-aware escaping for template syntax
PoC
# Replace the agent.start() call at line 85 with:
result = agent.start('Create file with content: {{ self.__init__.__globals__.__builtins__.__import__("os").system("touch /tmp/pwned") }}')
Successful exploitation creates /tmp/pwned confirming arbitrary command execution. The expression {{7*7}} renders as 49 instead of literal text.
Impact
Attackers can execute arbitrary system commands with the privileges of the running process by injecting malicious template expressions through agent instructions. This compromises the host system, enabling data theft, ransomware deployment, or lateral movement.
Recommended Fix
- Input Sanitization: Implement strict whitelist validation for file content
- **Context…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-39891 has been found in praisonai.
Attackers can target a specific entry point like acp_create_file over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade praisonai to 4.5.115 or later.
If unsure, ask your IT team or search "praisonai CVE-2026-39891" on the vendor's site.
CVE-2026-39891 (praisonai) — CWE-94 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: acp_create_file
Patched: 4.5.115 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Arbitrary code execution (CWE-94) exists in praisonai. Attackers reach the vulnerable code path via acp_create_file.
Check the vendor advisory for the affected versions of praisonai. Attack surface: acp_create_file.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to 4.5.115.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'praisonai' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'praisonai' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
praisonaiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade praisonai to 4.5.115ステージング環境で 4.5.115 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com