CVE-2021-29432
Malicious users could control the content of invitation emails
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Malicious users could control the content of invitation emails
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.
- Record
CVE-2021-29432- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2021-0121
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.
- Record
EUVD-2021-0121- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mh74-4m5g-fcjx
Malicious users could abuse Sydent to control the content of invitation emails
Impact
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.
Patches
Fixed in 4469d1d, 6b405a8, 65a6e91.
Note that these patches include changes to the default email templates. If these templates have been locally modified, they must also be updated.
For more information
If you have any questions or comments about this advisory, email us at [email protected].
- Record
GHSA-mh74-4m5g-fcjx- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-29432- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-29432- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-mh74-4m5g-fcjx
Malicious users could abuse Sydent to control the content of invitation emails
Impact
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.
Patches
Fixed in 4469d1d, 6b405a8, 65a6e91.
Note that these patches include changes to the default email templates. If these templates have been locally modified, they must also be updated.
For more information
If you have any questions or comments about this advisory, email us at [email protected].
- Record
GHSA-mh74-4m5g-fcjx- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
OSVPYSEC-2021-23 No score
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.
- Record
PYSEC-2021-23- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
matrix-sydentPyPI |
before 2.3.0 | 2.3.0 |
matrix-sydentPyPI |
before 2.3.0, plus listed versions 2.0.02.0.12.1.02.2.0 |
2.3.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-29432 is a medium vulnerability (CVSS 5.3) in Matrix Sydent, published April 15, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.93%, the 60th percentile. Fixed in matrix-sydent 2.3.0.
References
pypi.org/project/matrix-sydent
github.com/matrix-org/sydent/releases/tag/v2.3.0
nvd.nist.gov/vuln/detail/CVE-2021-29432