CVE-2026-9205: Langflow: Weak Fernet Key via random.seed()

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.3%, percentile 22: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 22% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes langflow (PyPI) <= 1.10.0, fixed in 1.10.1. Check your lockfile, including transitive dependencies.

What it is

IBM Langflow OSS contains a weak cryptographic key derivation vulnerability in the ensurefernetkey() function.

From the GitHub advisory

Summary

Langflow uses Python's random module (Mersenne Twister, a non-cryptographic PRNG) seeded with the SECRETKEY to derive the Fernet encryption key for all stored user credentials (API keys, LLM provider secrets, database passwords). When the SECRETKEY is shorter than 32 characters — a common scenario for self-hosted deployments using simple/memorable secrets — the derived encryption key is fully deterministic and reproducible by anyone who knows the seed value. An attacker who obtains the SECRETKEY (e.g., via the MCP path traversal in this repo) can reconstruct the exact Fernet key offline and decrypt every credential stored in the database with no brute force required.

Even when SECRETKEY is 32+ characters (the "safe" branch), the raw key material is used directly as the Fernet key — meaning exfiltrating the secretkey file is sufficient to decrypt all credentials without any additional computation.

Severity: Critical — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N (9.1) CWE-338: Weak PRNG | CWE-321: Hard-coded Cryptographic Key | CWE-311: Missing Encryption of Sensitive Data

Details

Weakness type: CWE-338, CWE-228.

Product: langflow (PyPI) · Assigned by: ibm · Published: 2026-08-05

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.30% probability of exploitation activity in the next 30 days; percentile 22.

Timeline

• 2026-08-05 — CVE record published by ibm
• 2026-08-07 — CVE record last updated
• 2026-10-05 — GitHub-reviewed advisory GHSA-jxw3-mjmx-3pqm published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. ibm.com ibm.com

Vulnerability records

1. GitHub Advisory GHSA-jxw3-mjmx-3pqm github.com
2. CVE.org record CVE-2026-9205 cve.org
3. NVD entry CVE-2026-9205 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical PyPI advisories · Today’s Security Digest