CVE-2026-77776

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.61% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 49.1% of scored records. A rank, not a probability.

NVD base score

9.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Deferred. NVD last modified this record on 2026-10-15.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-08-21 11:22Z2 MO AGO

Last updated

2026-08-21 21:44Z2 MO AGO

Reserved

2026-08-21

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Critical (CVSS 9.3)

CNA CVSS vector

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

Weaknesses

• CWE-639Authorization Bypass Through User-Controlled KeyBase

Data version

5.2

Document digest

ce8daaa8e350611ce85a2e7e36afacd3928e6301ca326d4f57b3cdbad694f4da

• github.comPull Request #2207 addressing the assessment findingshttps://github.com/headroomlabs-ai/headroom/pull/2207issue-tracking
• github.comHeader handling in the OpenAI proxy handler at v0.29.0https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.pytechnical-description
• github.comresolve_memory_identity seam introduced by the fixhttps://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.pytechnical-description
• github.comhttps://github.com/headroomlabs-ai/headroomproduct
• www.vulncheck.comVulnCheck Advisory: Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identityhttps://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identitythird-party-advisory