Vulnerability Description
Use of a One-Way Hash with a Predictable Salt vulnerability in team-alembic AshAuthentication allows readers of the audit store to recover the client IP addresses that the audit log add-on's :hash privacy mode is meant to pseudonymise. AshAuthentication.AddOn.AuditLog.IpPrivacy.hash_ip/1 computes a single unkeyed :crypto.hash(:sha256, salt <> ip) and truncates the result to 16 hexadecimal characters. The salt is read from the :audit_log_ip_salt or :secret application config keys, and falls back to the constant "default-salt-change-in-production" published in the library source when neither is set, with nothing warning that the default is in use. The IPv4 space is only 2^32 values and SHA-256 is fast, so the whole hash table is precomputable and every stored value maps back to its source address. Truncating to 16 characters does not help, and even a configured salt leaves the hash cheap enough to enumerate once it leaks. This issue affects ash_authentication: from 4.12.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-82759.html
- https://github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f
- https://github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0
- https://github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc83461
- https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj
- https://osv.dev/vulnerability/EEF-CVE-2026-82759
FAQ
What is CVE-2026-82759?
CVE-2026-82759 is a documented vulnerability. Use of a One-Way Hash with a Predictable Salt vulnerability in team-alembic AshAuthentication allows readers of the audit store to recover the client IP addresses that the audit log add-on's :hash pri...
How severe is CVE-2026-82759?
CVSS scoring is not yet available for CVE-2026-82759. Check NVD for updates.
Is there a patch for CVE-2026-82759?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.