---
id: CVE-2026-82759
title: >-
  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.


  …
summary: >-
  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.


  …
severity: low
cvss: 1.8
cvssVector: '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'
cwe:
  - CWE-760
vendor: team-alembic
product: ash_authentication
affected:
  - ash_authentication >= 4.12.0 < 4.15.0
  - ash_authentication >= 5.0.0-rc.0 < 5.0.0-rc.14
  - >-
    team-alembic/ash_authentication >= 255cfc9c0e511b7e0de39f8b3d676ae994fae06c
    < *
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:16:18.527'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82759'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-82759.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f8b3d676ae994fae06c
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0402db0a96638479478
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc8346198d5e4f588b5937541
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj-pcpq-xhfm
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-82759'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
tags:
  - nvd
  - cve.org
epss: 0.00139
epssPercentile: 0.02715
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T18:19:03.885925Z'
cvssSource: cna
ingestedAt: '2026-09-17T13:18:16.987Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.