{"id":"CVE-2026-82759","state":"PUBLISHED","title":"Reversible IP address pseudonymisation in AshAuthentication audit log hash mode","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.\n\nAshAuthentication.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.\n\nThis 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.","publishedAt":"2026-09-17T13:08:21.929Z","updatedAt":"2026-09-17T18:19:18.209Z","severity":{"score":1.8,"label":"Low","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["team-alembic ash_authentication"],"affected":[{"vendor":"team-alembic","product":"ash_authentication","packageName":"ash_authentication","packageURL":"pkg:hex/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"4.12.0","status":"affected","lessThan":"4.15.0","versionType":"semver"},{"version":"5.0.0-rc.0","status":"affected","lessThan":"5.0.0-rc.14","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy'"],"programFiles":["lib/ash_authentication/add_ons/audit_log/ip_privacy.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':hash_ip/1"},{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':apply_privacy/3"}],"repo":"https://github.com/team-alembic/ash_authentication"},{"vendor":"team-alembic","product":"ash_authentication","packageName":"team-alembic/ash_authentication","packageURL":"pkg:github/team-alembic/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"255cfc9c0e511b7e0de39f8b3d676ae994fae06c","status":"affected","lessThan":"*","changes":[{"at":"d8a9c4b6bde828fdc8346198d5e4f588b5937541","status":"unaffected"},{"at":"c3a6d5fe0d4fd383ea81b0402db0a96638479478","status":"unaffected"}],"versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy'"],"programFiles":["lib/ash_authentication/add_ons/audit_log/ip_privacy.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':hash_ip/1"},{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':apply_privacy/3"}],"repo":"https://github.com/team-alembic/ash_authentication"}],"references":["https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj-pcpq-xhfm","https://cna.erlef.org/cves/CVE-2026-82759.html","https://osv.dev/vulnerability/EEF-CVE-2026-82759","https://github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f8b3d676ae994fae06c","https://github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc8346198d5e4f588b5937541","https://github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0402db0a96638479478"],"weaknesses":["CWE-760"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82759.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82759","state":"PUBLISHED","datePublished":"2026-09-17T13:08:21.929Z","dateUpdated":"2026-09-17T18:19:18.209Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-31T01:00:10.817Z"},"containers":{"cna":{"title":"Reversible IP address pseudonymisation in AshAuthentication audit log hash mode","descriptions":[{"lang":"en","value":"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.\n\nAshAuthentication.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.\n\nThis 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."}],"affected":[{"vendor":"team-alembic","product":"ash_authentication","packageName":"ash_authentication","packageURL":"pkg:hex/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"4.12.0","status":"affected","lessThan":"4.15.0","versionType":"semver"},{"version":"5.0.0-rc.0","status":"affected","lessThan":"5.0.0-rc.14","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy'"],"programFiles":["lib/ash_authentication/add_ons/audit_log/ip_privacy.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':hash_ip/1"},{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':apply_privacy/3"}],"repo":"https://github.com/team-alembic/ash_authentication"},{"vendor":"team-alembic","product":"ash_authentication","packageName":"team-alembic/ash_authentication","packageURL":"pkg:github/team-alembic/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"255cfc9c0e511b7e0de39f8b3d676ae994fae06c","status":"affected","lessThan":"*","changes":[{"at":"d8a9c4b6bde828fdc8346198d5e4f588b5937541","status":"unaffected"},{"at":"c3a6d5fe0d4fd383ea81b0402db0a96638479478","status":"unaffected"}],"versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy'"],"programFiles":["lib/ash_authentication/add_ons/audit_log/ip_privacy.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':hash_ip/1"},{"name":"'Elixir.AshAuthentication.AddOn.AuditLog.IpPrivacy':apply_privacy/3"}],"repo":"https://github.com/team-alembic/ash_authentication"}],"references":[{"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj-pcpq-xhfm","tags":["related","vendor-advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-82759.html","name":"EEF CNA record for CVE-2026-82759","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-82759","name":"OSV record EEF-CVE-2026-82759","tags":["related"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f8b3d676ae994fae06c","name":"Introducing commit 255cfc9 in team-alembic/ash_authentication","tags":["related"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc8346198d5e4f588b5937541","name":"Fix commit d8a9c4b in team-alembic/ash_authentication","tags":["patch"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0402db0a96638479478","name":"Fix commit c3a6d5f in team-alembic/ash_authentication","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"LOCAL","baseScore":1.8,"baseSeverity":"LOW","privilegesRequired":"HIGH","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-760","description":"CWE-760 Use of a One-Way Hash with a Predictable Salt","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-09-17T13:08:21.929Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"

Only applications that enable the audit_log add-on and set its ip_privacy mode to :hash store the affected value. Other modes (:none, :truncate, :exclude) do not reach hash_ip/1.

\n

The complete break additionally requires the default salt, that is neither :audit_log_ip_salt nor :secret configured under the :ash_authentication application. This is the out-of-the-box state: no warning or error is raised when the hardcoded salt is in use.

"},{"base64":false,"type":"text/markdown","value":"Only applications that enable the `audit_log` add-on and set its `ip_privacy` mode to `:hash` store the affected value. Other modes (`:none`, `:truncate`, `:exclude`) do not reach `hash_ip/1`.\n\nThe complete break additionally requires the default salt, that is neither `:audit_log_ip_salt` nor `:secret` configured under the `:ash_authentication` application. This is the out-of-the-box state: no warning or error is raised when the hardcoded salt is in use."}],"value":"Only applications that enable the audit_log add-on and set its ip_privacy mode to :hash store the affected value. Other modes (:none, :truncate, :exclude) do not reach hash_ip/1.\n\nThe complete break additionally requires the default salt, that is neither :audit_log_ip_salt nor :secret configured under the :ash_authentication application. This is the out-of-the-box state: no warning or error is raised when the hardcoded salt is in use."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*","versionEndExcluding":"4.15.0","versionStartIncluding":"4.12.0","vulnerable":true},{"criteria":"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*","versionEndExcluding":"5.0.0-rc.14","versionStartIncluding":"5.0.0-rc.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"},{"lang":"en","type":"remediation developer","value":"James Harton"},{"lang":"en","type":"reporter","value":"Peter Ullrich"}],"dateAssigned":"2026-09-11T17:53:27.000Z","impacts":[{"capecId":"CAPEC-112","descriptions":[{"lang":"en","value":"CAPEC-112 Brute Force"}]}],"source":{"discovery":"INTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T18:19:03.885925Z","id":"CVE-2026-82759","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-17T18:19:18.209Z"}}]}}}