EUVD-2026-81477Severity by source
CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:L/VI:N/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
Requires existing read access to the audit store (PR:H, AV:L); reversing the hash is computationally cheap (AC:L); only pseudonymised client IPs are exposed (C:L), with no integrity or availability impact.
Primary rating from Vendor (EEF).
CVSS VectorVendor: EEF
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
The audit-log add-on in AshAuthentication stores pseudonymised client IP addresses using an unkeyed SHA-256 over a salt concatenated with the IP, truncated to 16 hex characters, so anyone who can already read the audit store can reverse those values back to the original addresses. Exploitation requires two explicit prerequisites: ip_privacy_mode must be set to :hash (the DSL default is :none, so this is an opt-in), and the attacker must already hold read access to the audit log via a database dump, backup, replica, or reader account. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires two concrete prerequisites: (1) the audit_log add-on must be configured on a resource with ip_privacy_mode set to :hash (the DSL default is :none, so this is an explicit opt-in), and (2) the attacker must already have read access to the stored audit log - a database dump, backup, replica, or a reader role/account over the audit store. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuinely low-priority issue, and the signals are consistent rather than conflicting. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: AshAuthentication 4.15.0 for the 4.x line and 5.0.0-rc.14 for the 5.x release-candidate line. … Detailed patch versions, workarounds, and compensating controls in full report. |
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