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CVE-2026-31943

Librechat server-side request forgery (SSRF)

8.5 HIGHPublic exploitEPSS 0.30%
  1. Published27 Mar 2026

Description

LibreChat is a ChatGPT clone with additional features. Prior to version 0.8.3, `isPrivateIP()` in `packages/api/src/auth/domain.ts` fails to detect IPv4-mapped IPv6 addresses in their hex-normalized form, allowing any authenticated user to bypass SSRF protection and make the server issue HTTP requests to internal network resources — including cloud metadata services (e.g., AWS `169.254.169.254`), loopback, and RFC1918 ranges. Version 0.8.3 fixes the issue.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Affected products

Librechat< 0.8.3 · 0.8.3

Remediation

Fixed in
Librechat≥ 0.8.3

References

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Frequently asked

Is CVE-2026-31943 being actively exploited?

CVE-2026-31943 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.30%.

How severe is CVE-2026-31943?

CVE-2026-31943 has a CVSS 3.1 base score of 8.5, rated high. EPSS estimates a 0.30% probability of exploitation.

Which products are affected by CVE-2026-31943?

Affected products include Librechat.

How do I fix CVE-2026-31943?

Upgrade affected software to a fixed version, for example Librechat 0.8.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-31943 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.