NVD / CVE Program· CNA EEF

CVE-2026-88952: OAuth2 sign-in attached to an existing account without an email comparison in AshAuthentication

Noroxi assessment

Priority: Monitor (action score 36/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.74% (FIRST EPSS); higher than 55% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: team-alembic ash_authentication 2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba, 4.15.0, 5.0.0-rc.14.

Low priority for now. Upgrade to team-alembic ash_authentication 2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba, 4.15.0, 5.0.0-rc.14 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker to be signed in as another user by linking an OAuth2 identity to an account that is not theirs. AshAuthentication.Strategy.OAuth2.UserResolver.resolve/3 matches an existing account using the register action's upsert_identity keys, then gates linking the incoming provider identity to it on email_trusted?/2, which reads only the provider's email_verified boolean and never compares the provider's email value with the matched account's email. That gate assumes the account was matched by its email field, so under any other upsert_identity it is vacuous and an attacker presenting their own verified email is attached to, and issued a session for, an account matched on some other attribute. The same unguarded gate applies in OAuth2.SignInPreparation on the registration_enabled? false path, where the account is matched by the sign-in action's read filter instead. The upsert also rewrites the matched account's email to the attacker's address, so later account recovery reaches the attacker rather than the owner. This issue affects ash_authentication: from 4.14.0 before 4.15.0 and from 5.0.0-rc.10 before 5.0.0-rc.14.

CriticalCVSS 9.1 · v4.0—No exploit Fix available

Published: Sep 17, 2026
Updated: Sep 18, 2026
EPSS: 0.7% · 55th percentile
CWE: CWE-287

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 36 / 40 · 9.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.7%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · EEF: 9.1; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

team-alembic ash_authentication
- 4.14.0 and later · before 4.15.0affected · semver
- 5.0.0-rc.10 and later · before 5.0.0-rc.14affected · semver
- 64530644f9b37ebb76ca14aeb83a77597a0034b7 and lateraffected · gitfixed in 738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459, 2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba
- 42edcd8ebb13fafbb168f12591d7518ce0611fec and lateraffected · gitfixed in 738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459, 2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Hex	ash_authentication	from 4.14.0 · before 4.15.0	4.15.0
Hex	ash_authentication	from 5.0.0-rc.10 · before 5.0.0-rc.14	5.0.0-rc.14

Same product

team-alembic: all records

Other highest-scoring records for the same primary product.

CVE-2026-76949Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacement
36Monitor
CVE-2026-91039dynamic_oidc identities are not namespaced by connection in ash_authentication, allowing cross-connection account takeover
36Monitor
CVE-2026-86533Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix
36Monitor

Published before and after this one in the same product

← EarlierCVE-2026-85500Sep 17, 2026 · `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthentication
36Monitor
← EarlierCVE-2026-86522Sep 17, 2026 · Log injection via an unescaped password reset identity in AshAuthentication
25Monitor
Later →CVE-2026-86688Sep 17, 2026 · Session id is not renewed on authentication in ash_authentication, allowing session fixation
29Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
team-alembic ash_authentication	2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba	Vendor (CNA)
team-alembic ash_authentication	4.15.0	Vendor (CNA)
team-alembic ash_authentication	5.0.0-rc.14	Vendor (CNA)
team-alembic ash_authentication	738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459	Vendor (CNA)
Hex:ash_authentication	4.15.0	Package registry (OSV)
Hex:ash_authentication	5.0.0-rc.14	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

James Hartonfinder
Jonatan Männchen / EEFcoordinator

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-802180 days apartSign-in token minted for one resource accepted by another in AshAuthentication
30Monitor
CVE-2026-6563323 days apartPurpose-limited JWT accepted as full bearer authentication in AshAuthentication
30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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

nvd-secondary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1app.use("/admin", requireSession, adminRouter);
2

3// Route added later skips the middleware
4app.post("/admin-api/config", updateConfig);

Fixed

1const admin = express.Router();
2admin.use(requireSession, requireRole("admin"));
3

4admin.post("/config", updateConfig);
5app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

Fix✗ → ✓Sep 28, 2026, 10:07 PM UTC

For records you follow, these changes also arrive as notifications. →

References

cna.erlef.org/cves/CVE-2026-88952.html

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records