CVE-2024-9277: Langflow: ReDoS crashes LLM workflow backend via HTTP POST
GHSA-355v-2rjx-fpx7 MEDIUM PoC AVAILABLE CISA: TRACK*Any low-privilege authenticated user can hang or crash Langflow's backend by sending a crafted HTTP POST request that triggers catastrophic regex backtracking. No patch was available at disclosure and the vendor was unresponsive — if your team runs Langflow ≤1.0.18 for AI pipeline orchestration, restrict API access to trusted networks immediately. No data exfiltration risk, but full availability loss of your LLM workflow layer is trivially achievable.
Risk Assessment
Medium operational risk with high availability impact if exploited. Network-accessible with low-privilege authentication required — any registered Langflow user can trigger it. PoC is public. EPSS is very low (0.17%) indicating limited in-the-wild exploitation, but the attack requires no AI/ML expertise: just a crafted string sent to an HTTP endpoint. Organizations exposing Langflow to internal users or via API are meaningfully exposed until patched or mitigated.
Affected Systems
Severity & Risk
Attack Surface
Recommended Action
7 steps-
Upgrade Langflow beyond 1.0.18 — check the official GitHub for the first release addressing CWE-1333 in utils.py.
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If no patch available, restrict Langflow API access to explicitly trusted internal IP ranges via firewall or reverse proxy ACLs.
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Enforce authentication controls — ensure no anonymous access to HTTP POST endpoints.
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Implement request timeouts and CPU limits at the process/container level to bound the impact of any single request.
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Deploy rate limiting on the POST endpoint to slow brute-force DoS attempts.
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Monitor for CPU spike patterns in Langflow processes as a detection signal — a single malicious request can peg a CPU core to 100%.
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Reference the PoC at the Notion advisory URL for reproduction details to validate fixes.
CISA SSVC Assessment
Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.
Classification
Compliance Impact
This CVE is relevant to:
Frequently Asked Questions
What is CVE-2024-9277?
Any low-privilege authenticated user can hang or crash Langflow's backend by sending a crafted HTTP POST request that triggers catastrophic regex backtracking. No patch was available at disclosure and the vendor was unresponsive — if your team runs Langflow ≤1.0.18 for AI pipeline orchestration, restrict API access to trusted networks immediately. No data exfiltration risk, but full availability loss of your LLM workflow layer is trivially achievable.
Is CVE-2024-9277 actively exploited?
Proof-of-concept exploit code is publicly available for CVE-2024-9277, increasing the risk of exploitation.
How to fix CVE-2024-9277?
1. Upgrade Langflow beyond 1.0.18 — check the official GitHub for the first release addressing CWE-1333 in utils.py. 2. If no patch available, restrict Langflow API access to explicitly trusted internal IP ranges via firewall or reverse proxy ACLs. 3. Enforce authentication controls — ensure no anonymous access to HTTP POST endpoints. 4. Implement request timeouts and CPU limits at the process/container level to bound the impact of any single request. 5. Deploy rate limiting on the POST endpoint to slow brute-force DoS attempts. 6. Monitor for CPU spike patterns in Langflow processes as a detection signal — a single malicious request can peg a CPU core to 100%. 7. Reference the PoC at the Notion advisory URL for reproduction details to validate fixes.
What systems are affected by CVE-2024-9277?
This vulnerability affects the following AI/ML architecture patterns: agent frameworks, LLM orchestration platforms, AI workflow automation, multi-step AI pipelines.
What is the CVSS score for CVE-2024-9277?
CVE-2024-9277 has a CVSS v3.1 base score of 6.5 (MEDIUM). The EPSS exploitation probability is 0.17%.
Technical Details
NVD Description
A vulnerability classified as problematic was found in Langflow up to 1.0.18. Affected by this vulnerability is an unknown functionality of the file \src\backend\base\langflow\interface\utils.py of the component HTTP POST Request Handler. The manipulation of the argument remaining_text leads to inefficient regular expression complexity. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Exploitation Scenario
An attacker with a low-privilege Langflow account (e.g., a developer or contractor with basic access) sends a crafted HTTP POST request to the Langflow backend. The `remaining_text` parameter contains input engineered to trigger catastrophic backtracking in the regex pattern within utils.py — a classic ReDoS payload. The regex engine enters an exponential execution loop, consuming 100% of a CPU core. With a small number of concurrent requests, the attacker saturates all available CPU threads, making the Langflow service unresponsive. All active AI workflows, agent pipelines, and API consumers are immediately disrupted. The attacker needs no knowledge of the underlying LLM models, only the ability to send HTTP requests.
Weaknesses (CWE)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H References
- rumbling-slice-eb0.notion.site/Remote-Redos-in-https-github-com-langflow-ai-langflow-067159ced0d5494e91b06071384969c4 Exploit 3rd Party
- vuldb.com Permissions Required VDB
- vuldb.com 3rd Party VDB
- vuldb.com 3rd Party VDB
- github.com/advisories/GHSA-355v-2rjx-fpx7
- github.com/langflow-ai/langflow/blob/main/src/backend/base/langflow/interface/utils.py
- nvd.nist.gov/vuln/detail/CVE-2024-9277
Timeline
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