GO · JULY 2026 · EARLY WARNING

Cosmos-Server Authentication Bypass via Header Smuggling Under Investigation

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
GHSA-2RX5-2G7J-2659Severity: HIGH

An authentication bypass vulnerability via forward-auth header smuggling on the Constellation tunnel in Cosmos-Server is under investigation. Users of Cosmos-Server versions up to 0.22.18 should review and update to the latest version.

What happened

An early warning has been issued regarding a potential authentication bypass vulnerability in Cosmos-Server. This vulnerability, tracked as GHSA-2RX5-2G7J-2659, reportedly allows an attacker to bypass authentication by setting specific headers. The issue appears to affect versions of Cosmos-Server up to 0.22.18. It is recommended that users review their installations and update to the latest version to mitigate this risk. The primary source for more details is the GitHub advisory at https://github.com/azukaar/Cosmos-Server/security/advisories/GHSA-2rx5-2g7j-2659.

How 0Day mitigates this

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