Is CVE-2026-31951 in the CISA KEV catalog?

No. CVE-2026-31951 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-31951?

CVE-2026-31951 has a CVSS v3 base score of 6.8 (MEDIUM).

What is the EPSS score for CVE-2026-31951?

CVE-2026-31951 has an EPSS score of 0.24% (15th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-31951?

Upgrade librechat to 0.8.3 or later.

CVE & CISA-KEV Catalog

CVE-2026-31951

MEDIUM

6.8

CVSS v3

NVD

Description

LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc1 through 0.8.3-rc1, user-created MCP (Model Context Protocol) servers can include arbitrary HTTP headers that undergo credential placeholder substitution. An attacker can create a malicious MCP server with headers containing `{{LIBRECHAT_OPENID_ACCESS_TOKEN}}` (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated. Version 0.8.3-rc2 fixes the issue.

CWE-200Information Exposure

How to fix

Remediation Available

librechatNVD

Affected:>= 0.8.2, < 0.8.3Fixed in:0.8.3CVE-2026-31951derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeChanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N

Exploit Intelligence

0.24%probability of exploitation in 30 days

15thpercentile

Low risk: more likely to be exploited than 15% of all known CVEs.

References

Exploit1

github.com

Related Vulnerabilities

Other CWE-200 (Information Exposure) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-24919	High	8.6	100%	KEV + Ransom	-
CVE-2020-14181	Medium	5.3	100%	-	Fix
CVE-2021-34429	Medium	5.3	99%	-	Fix
CVE-2018-11409	Medium	5.3	98%	-	-
CVE-2021-41277	Critical	10.0	97%	KEV	-
CVE-2016-2183	High	7.5	96%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-30.