CVE-2026-31943: LibreChat is a ChatGPT clone with additional features

Q: How do I fix CVE-2026-31943?

librechat: upgrade to 0.8.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-31943 being exploited?

CVE-2026-31943 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-31943 affect?

CVE-2026-31943 affects librechat. Severity is high (CVSS 8.5). 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

Q: How urgent is CVE-2026-31943?

Priority 38/100. High severity; Public exploit reference

Routine

HIGH 8.5UPGRADE

CVE-2026-31943 is a high-severity flaw (CVSS 8.5) affecting librechat. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-918
Published	2026-03-27
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: librechat

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-27 20:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

librechat librechat UPGRADE

Affected: < 0.8.3 · 0.8.3 rc1 · 0.8.3 rc2

Fixed in: 0.8.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy librechat || rpm -q librechat || librechat --version

2. UPGRADE to 0.8.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade librechat

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade librechat

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-31943?

librechat: upgrade to 0.8.3. Exact commands for each OS are on this page.

Is CVE-2026-31943 being exploited?

CVE-2026-31943 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-31943 affect?

CVE-2026-31943 affects librechat. Severity is high (CVSS 8.5). 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

How urgent is CVE-2026-31943?

Priority 38/100. High severity; Public exploit reference

Software pages

OpenAI ChatGPT vulnerabilities · AWS vulnerabilities

Related CVEs

CVE-2026-31945 HIGH 7.7 DOWNGRADE LibreChat is a ChatGPT clone with additional features
CVE-2026-31951 MEDIUM 6.8 UPGRADE LibreChat is a ChatGPT clone with additional features
CVE-2026-31950 MEDIUM 5.3 DOWNGRADE LibreChat is a ChatGPT clone with additional features
CVE-2026-54033 HIGH 7.7 UPGRADE LibreChat is an enhanced ChatGPT clone that supports multiple AI providers
CVE-2026-54037 MEDIUM 6.5 UPGRADE LibreChat is an enhanced ChatGPT clone that supports multiple AI providers

References

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