CVE-2026-49468: LiteLLM Proxy: authentication bypass via Host header spoofing
CVE-2026-49468 is a critical authentication bypass (CWE-290) in the LiteLLM proxy before 1.84.0. A crafted Host header can make the authentication layer evaluate a different route from the one actually dispatched, which may expose protected management routes without authentication under specific conditions. The record indicates a fix in 1.84.0, and the vulnerability is not listed in CISA KEV.
Overview
LiteLLM is a proxy server (AI Gateway) used to call LLM APIs in OpenAI or native format. CVE-2026-49468 is a flaw in how the proxy parses the Host header. The authentication layer derives the effective route from the request path, and that path is reconstructed from the Host header, so the route checked for authentication can differ from the route actually handled.
Impact
According to the record, the flaw could, under specific conditions, allow unauthenticated access to protected management routes. NVD and GitHub rate it as critical, with a CVSS 3.1 base score of 9.8 from NVD and a CVSS 4.0 score of 9.5 from GitHub. The weakness is classified as CWE-290, Authentication Bypass by Spoofing.
Affected products and versions
- LiteLLM (product listed as Litellm Litellm) in versions before 1.84.0.
- The record lists no other affected version ranges.
Exploitation status
CISA KEV does not list this CVE in the record. No confirmed active exploitation or exploitation in the wild appears in the sources consulted for this analysis.
Remediation and mitigation
- The record states the vulnerability is fixed in version 1.84.0. Upgrading to that version or later is the primary recommended action; see the vendor advisory and the release notes for v1.84.0.
- Until the upgrade is applied, operators can reduce exposure by restricting which hostnames reach the proxy at the network or reverse-proxy layer and by limiting access to management interfaces to trusted networks. These are general hardening measures, not vendor-confirmed workarounds.
Detection guidance
- Review proxy and reverse-proxy logs for requests to management routes that carry unexpected or unrecognized Host header values.
- Look for successful management-route responses from sources that should not have access, and correlate them with Host header anomalies.
- Monitor for configuration or key changes on the proxy that were not made by authorized administrators.
Limitations of the available information
The record does not specify which management routes are affected, what the specific conditions are, or whether the issue has been demonstrated in production deployments. No EPSS score or SSVC data is present. The record's CVSS 3.1 scores include 9.8 from NVD and 8.1 from another provider; the provider for the 8.1 score is identified only by an identifier. Whether a given deployment is exposed depends on its configuration, which the record does not describe.
Frequently asked questions
Which LiteLLM versions are affected by CVE-2026-49468?
The record lists LiteLLM versions before 1.84.0 as affected. The fix is stated to be included in 1.84.0.
Is CVE-2026-49468 known to be actively exploited?
The record shows it is not listed in CISA KEV, and no confirmed active exploitation appears in the sources consulted for this analysis.
What is the main recommended action?
Upgrade LiteLLM to version 1.84.0 or later, as indicated by the vendor advisory and release notes, and restrict network access to management interfaces while you do so.
This analysis was drafted with AI assistance from verified source data and automatically checked against it.