team-alembic ash_authentication up to 4.14.x/5.0.0-rc.13 AuditLog hash predictable salt

Summaryinfo

A vulnerability was found in team-alembic ash_authentication up to 4.14.x/5.0.0-rc.13. It has been declared as problematic. This vulnerability affects the function AshAuthentication.AddOn.AuditLog.IpPrivacy.hash_ip of the component AuditLog. The manipulation results in hash predictable salt. This vulnerability was named CVE-2026-82759. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in team-alembic ash_authentication up to 4.14.x/5.0.0-rc.13. Affected is the function AshAuthentication.AddOn.AuditLog.IpPrivacy.hash_ip of the component AuditLog. The manipulation with an unknown input leads to a hash predictable salt vulnerability. CWE is classifying the issue as CWE-760. The product uses a one-way cryptographic hash against an input that should not be reversible, such as a password, but the product uses a predictable salt as part of the input. This is going to have an impact on confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-82759 since 08/31/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Additional levels of successful authentication are necessary for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1110.002 by the MITRE ATT&CK project.

Upgrading to version 4.15.0 or 5.0.0-rc.14 eliminates this vulnerability.

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Productinfo

Vendor

• team-alembic

Name

• ash_authentication

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 5.0.0-rc.0
• 5.0.0-rc.1
• 5.0.0-rc.2
• 5.0.0-rc.3
• 5.0.0-rc.4
• 5.0.0-rc.5
• 5.0.0-rc.6
• 5.0.0-rc.7
• 5.0.0-rc.8
• 5.0.0-rc.9
• 5.0.0-rc.10
• 5.0.0-rc.11
• 5.0.0-rc.12
• 5.0.0-rc.13

Website

• Product: https://github.com/team-alembic/ash_authentication/

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