CVE-2026-82759 — Reversible IP address pseudonymisation in AshAuthentication audit log hash mode
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- No scoring signals.
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Team-alembic Ash Authentication).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Team-alembic | Ash Authentication | ≥ 4.12.0 and < 4.15.0≥ 5.0.0-rc.0 and < 5.0.0-rc.14≥ 255cfc9c0e511b7e0de39f8b3d676ae994fae06c | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 1.8 | CVSS 4.0 | Low | — | — | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db via NIST National Vulnerability Database |
| 1.8 | CVSS 4.0 | Low | — | — | EEF via CVE Program (cve.org) e CISA ADP |
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 (score shown at the top: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · team-alembic/ash authentication
- SSVC assessment updated
- Record published
- CVSS changed · 1.8
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
6 on the record
- github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0402db0a9
- github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc8346198d5e4f5
- cna.erlef.org/cves/CVE-2026-82759.html
- github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f8b3d676a
- osv.dev/vulnerability/EEF-CVE-2026-82759
- github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj-pcpq-xh
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-86688 Session id is not renewed on authentication in ash_authentication, allowing session fixation 28d
- Critical CVE-2026-76949 Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacement 28d
- Critical CVE-2026-91039 dynamic_oidc identities are not namespaced by connection in ash_authentication, allowing cross-connection account takeover 28d
- Critical CVE-2026-88952 OAuth2 sign-in attached to an existing account without an email comparison in AshAuthentication 28d
- Critical CVE-2026-86533 Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix 28d
- Critical CVE-2026-85500 `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthentication 28d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-82759 is "Reversible IP address pseudonymisation in AshAuthentication audit log hash mode", rated Low. It affects Ash Authentication (Team-alembic); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 1.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.