NVD / CVE Program· CNA GitHub_M

CVE-2023-32682: Improper checks for deactivated users during login in synapse

Noroxi assessment

Priority: Monitor (action score 21/100)

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: 0.75% (FIRST EPSS); higher than 54.9% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: matrix-org synapse 1.85.0.

Low priority for now. Upgrade to matrix-org synapse 1.85.0 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

Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. In affected versions it may be possible for a deactivated user to login when using uncommon configurations. This only applies if any of the following are true: 1. JSON Web Tokens are enabled for login via the `jwt_config.enabled` configuration setting. 2. The local password database is enabled via the `password_config.enabled` and `password_config.localdb_enabled` configuration settings *and* a user's password is updated via an admin API after a user is deactivated. Note that the local password database is enabled by default, but it is uncommon to set a user's password after they've been deactivated. Installations that are configured to only allow login via Single Sign-On (SSO) via CAS, SAML or OpenID Connect (OIDC); or via an external password provider (e.g. LDAP) are not affected. If not using JSON Web Tokens, ensure that deactivated users do not have a password set. This issue has been addressed in version 1.85.0. Users are advised to upgrade.

MediumCVSS 5.4 · v3.1—No exploit Fix available

Auth bypass

Published: Jun 6, 2023
Updated: Jun 17, 2026
EPSS: 0.7% · 54th percentile
CWE: CWE-287

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 21 / 40 · 5.4 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.7%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 5.4
CNA · GitHub_M: 5.4; agree

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

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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.

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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.

Vendor	Product	CPE
matrix	synapse	cpe:2.3:a:matrix:synapse

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

matrix synapsebefore 1.85.0

Versions reported by the vendor

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

matrix-org synapse
- < 1.85.0affected

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
openSUSE:Tumbleweed	matrix-synapse	before 1.85.2-1.1	1.85.2-1.1
PyPI	matrix-synapse	before 1.85.0	1.85.0

Same product

matrix: all records

Other highest-scoring records for the same primary product.

CVE-2019-18835Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs.
39Monitor
CVE-2018-16515Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper tr
35Monitor
CVE-2024-52815Synapse allows a a malformed invite to break the invitee's `/sync`
34Monitor

Published before and after this one in the same product

← EarlierCVE-2022-39374May 26, 2023 · Synapse Denial of service due to incorrect application of event authorization rules during state resolution
26Monitor
← EarlierCVE-2023-32323May 26, 2023 · Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites
17Monitor
Later →CVE-2023-32683Jun 6, 2023 · URL deny list bypass via oEmbed and image URLs when generating previews in Synapse
21Monitor

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
matrix-org synapse	1.85.0 · description	Vendor (CNA)
debian:matrix-synapse	1.90.0-1 · Debian:14	Package registry (OSV)
opensuse:matrix-synapse	1.85.2-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
PyPI:matrix-synapse	1.85.0	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.

No history yet (it accumulates with the daily EPSS job).

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.

No credits in the CNA record.

Variant candidates

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

No nightly-computed relations.

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.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: low · data can be read
Integrity: low · data or configuration can be modified
Availability: none

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: Low
Integrity impact: Low
Availability impact: None

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

nvd-primary

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, 10:46 PM UTC

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References

github.com/matrix-org/synapse/pull/15624

Show all references (6 more)

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

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