Is there a public exploit for CVE-2026-77775?

No public exploit for CVE-2026-77775 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-77775?

CVE-2026-77775 scores CVSS 7.7 (v4.0), rated high. EPSS puts the chance of exploitation in the next 30 days at 0.59%.

What does CVE-2026-77775 affect?

CVE-2026-77775 affects Headroom Labs Headroom.

7.7 High

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header.

CVE-2026-77775

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. resolveopenaiupstreambase in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for use as the upstream base; selectpassthroughbaseurl in headroom/providers/proxyroutes.py reads the same header for the passthrough routes. No check rejects loopback, link-local, or RFC 1918 destinations, and because the component is a proxy the upstream response is returned to the caller, so the request reaches internal services and cloud metadata addresses and their responses are disclosed. The Authorization header accompanying the request is forwarded unchanged to the caller-designated host. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOMPROXYTOKEN, which the server itself warns about at startup, so a deployment following the shipped compose exposes the affected data-plane routes to the network without authentication.

Assessment

CVSS: 7.7 (v4.0)
Severity: High
EPSS: 0.59% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 21 August 2026
Last updated: 8 November 2026
Affected: Headroom Labs · Headroom
Assigner: VulnCheck

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

At the source

EUVD (ENISA)

References

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