Malicious users could control the content of invitation emails
Priority LOW 27CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
Sydent is a reference matrix identity server. A malicious user could abuse Sydent to send out arbitrary emails from the Sydent email address. This could be used to construct plausible phishing emails, for example. This issue has been fixed in 4469d1d.
Why it matters now
EPSS 0.00934 60th percentileScored 2026-11-07
Fix Fixed sydent (matrix-org): 2.3.0matrix-sydent (PyPI): 2.3.0
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| matrix-org | sydent | before 2.3.0 | 2.3.0 | Patch available | CNA |
| — | matrix-sydent (PyPI) | before 2.3.0 | 2.3.0 | Patch available | GHSA-mh74-4m5g-fcjx |
- sydent Vendormatrix-org Affected before 2.3.0 Fixed in 2.3.0 Patch available CNA
- matrix-sydent (PyPI) Vendor— Affected before 2.3.0 Fixed in 2.3.0 Patch available GHSA-mh74-4m5g-fcjx
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:* | before 2.3.0 | Vulnerable | matrix-org |
- cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:* Versions before 2.3.0 Vulnerable ·matrix-org
Remediation
- Fix · CNA sydent (matrix-org) Fixed in 2.3.0
- Fix · GHSA-mh74-4m5g-fcjx matrix-sydent (PyPI) Fixed in 2.3.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-29432
- 2026-10-03 Alias added: GHSA-mh74-4m5g-fcjx
References
Patch 2
Advisory 3
More matrix-org Sydent vulnerabilities
- TI-2023-20035 Sydent does not verify email server certificates CVSS 3.1CRITICAL 9.3
- TI-2021-10144 SSRF in Sydent due to missing validation of hostnames CVSS 3.1HIGH 7.7
- TI-2021-10143 Denial of service attack via memory exhaustion CVSS 3.1HIGH 7.5
- TI-2019-08878 An issue was discovered in Matrix Sydent before 1.0.3 and Synapse before 0.99.3.1. CVSS 3.0HIGH 7.5
- TI-2019-08469 util/emailutils.py in Matrix Sydent before 1.0.2 mishandles registration restrictions… CVSS 3.0MEDIUM 5.9
- TI-2021-10146 Denial of service (via resource exhaustion) due to improper input validation CVSS 3.1MEDIUM 4.3
Sources
- CVE-2021-29432 · CVE Program
- CVE-2021-29432 · NVD
- FIRST EPSS
- GHSA-mh74-4m5g-fcjx · GitHub Advisory Database · CC BY 4.0
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