Redash CVE-2026-77371

Requires (1) a Redash instance on 26.0.0 through pre-26.9.0 where an administrator has configured a DuckDB data source, and (2) an authenticated account that has been granted query access to that specific data source (PR:L). The flaw is that the DuckDB connection was opened with enable_external_access at its default true, so DuckDB's file-reading functions and COPY TO are available to any query user. Limiting factors: exploitation is not possible without an existing DuckDB source and a query-capable account, and only files readable/writable by the Redash OS process are exposed; instances not using the DuckDB query runner are unaffected.

This is a genuine high-priority issue rather than a CVSS-inflated one. The vendor CVSS 4.0 base score of 9.3 (AV:N/AC:L/AT:N/PR:L/UI:N) with high confidentiality, integrity and availability impact on both the vulnerable and subsequent systems (VC/VI/VA:H, SC/SI:H) is well-supported by the mechanism: a low-privileged but authenticated Redash user with query access to an administrator-created DuckDB data source can read or write arbitrary files as the Redash process, and crucially can read REDASH_COOKIE_SECRET / REDASH_SECRET_KEY to forge sessions and bypass authentication entirely - escalating from a limited query user to full application compromise. The key mitigating signal is PR:L: this is not remote-unauthenticated; the attacker must already hold a valid account with access to a configured DuckDB source. No EPSS score, CISA KEV listing, or public POC was provided in the input, so there is no evidence of active exploitation or automated weaponization at this time; the exploit code evidence is the fix-side commit, not an offensive POC. SSVC-style read: exploitation is 'none observed' per available data, technical impact is 'total', automatable is uncertain but low because an admin-configured DuckDB source and a query-capable account are both required. Net: prioritize patching for any deployment that uses the DuckDB query runner, but widespread opportunistic exploitation is unlikely given the preconditions.

An authenticated Redash user who has been granted query access to a DuckDB data source submits a query using DuckDB's native file functions (e.g. read_text) to read /opt/redash's environment or config files, extracting REDASH_COOKIE_SECRET. They then forge a signed session cookie to impersonate an administrator, achieving authentication bypass. No weaponized public POC was provided; the only published exploit-relevant code is the vendor's fix commit.