● Medium · CVSS 4.1

How to Fix CVE-2026-26019: Critical Vulnerability in langchainjs

Q: Is CVE-2026-26019 being exploited in the wild?

Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.

Q: Will a WAF or IDS rule fully mitigate CVE-2026-26019?

No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.

Q: How long should I plan for the upgrade?

Typical vendor-documented upgrade windows for langchainjs run from a few minutes to under an hour depending on cluster size. Test in a staging environment first and follow the vendor's documented HA upgrade order.

Other vulnerabilities in the same area that are worth patching alongside this one:

How to Fix CVE-2026-25099: Unrestricted File Upload in Bludit — Unrestricted File Upload in Bludit
How to Fix CVE-2026-25631: Input Validation Flaw in n8n — Input Validation Flaw in n8n
How to Fix CVE-2026-32692: Unauthorized update of out-of-scope Vault secrets in Juju , Unauthorized update of out-of-scope Vault secrets in Juju
How to Fix CVE-2026-2035: Command Injection in OPNsense , Command Injection in OPNsense
How to Fix CVE-2026-1215: Critical Vulnerability in MMA Call Tracking , Critical Vulnerability in MMA Call Tracking

*By Sai Kiran Pandrala*

⚡ At a glance


Severity	CVSS 4.1 - Medium
Actively exploited?	Not currently listed in CISA KEV
Affected	< 1.1.14
Fixed in	1.1.14.
Type (CWE)	CWE-918: Server-Side Request Forgery (SSRF)

What is CVE-2026-26019?

CVE-2026-26019 is a security flaw in langchainjs. LangChain is a framework for building LLM-powered applications. Prior to 1.1.14, the RecursiveUrlLoader class in @langchain/community is a web crawler that recursively follows links from a starting URL.

Why this CVE matters

Unpatched network-facing software is the leading initial-access vector in public breach reporting. Treat any CVSS-9 class flaw on an internet-reachable system as urgent, regardless of whether public exploit code has been observed yet.

For deployments of langchainjs that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.

Am I affected?

You are affected if your installation matches any of these version ranges:

langchainjs: < 1.1.14

Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.

Open langchainjs's About dialog or run the vendor-documented version-check command. Compare the result against the affected ranges in the advisory.

How to fix CVE-2026-26019

Read the vendor advisory in full: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7
Upgrade langchainjs to the patched build listed in the vendor advisory.
Back up the configuration (and database, where applicable) before upgrading.
Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
Restart the affected service so the patched binary loads, then verify the new version (see verification section).

Patched-version commands

Vendor advisory: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7

Affected: langchainjs: < 1.1.14

Patched in: 1.1.14


# Vendor advisory: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7

# npm / Yarn / pnpm.
npm install langchainjs@1.1.14
npm ls langchainjs

# Python / pip.
python -m pip install --upgrade "langchainjs>=1.1.14"
python -m pip show langchainjs

# Container image.
docker pull <your-registry>/langchainjs:1.1.14
docker stop langchainjs && docker rm langchainjs
docker run -d --name langchainjs <your-registry>/langchainjs:1.1.14


# Vendor advisory: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7
# Same flow from a Windows admin workstation.
npm install langchainjs@1.1.14
docker pull <your-registry>/langchainjs:1.1.14

Verify the fix landed


# Vendor advisory: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7
# Post-patch verification (replace <service> with the real service unit).
journalctl -u <service> --since "10 minutes ago"
dmesg --since "10 minutes ago"

# Re-scan with your vulnerability scanner (Nessus, Qualys, Tenable, OpenVAS).
# It should no longer flag CVE-2026-26019 on the patched target.

If you cannot patch immediately

Restrict access to the management interface to trusted internal IP addresses only. Block public access at the firewall and require VPN for any remote administration. Apply the patch as soon as a maintenance window allows.

How to verify the fix worked

After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
Confirm the patched build matches the version listed in the vendor advisory.
Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-26019.
Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.

If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for log entries that do not match your normal request patterns, especially repeated requests to the same uncommon endpoint, and any administrative changes you cannot tie back to a known operator.

Frequently asked questions

Is CVE-2026-26019 being exploited in the wild?