CVE-2021-29433 json
Denial of service (via resource exhaustion) due to improper input validation
published 2021-04-15 5 y ago modified 2026-09-10 1 mo ago also GHSA-pw4v-gr34-2553 , PYSEC-2021-24 , EUVD-2021-0122
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 60%
- public exploits
- 0
- none known
Summary
Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.
Patch / fix
- pypi matrix-sydent 2.3.0
- matrix sydent 2.3.0
Exploit prediction
0.93% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| NVD | 2.0 | 4.0 | AV:N/AC:L/Au:S/C:N/I:N/A:P |
| GitHub | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | matrix-sydent | <2.3.0 |
2.3.0 |
Affected products
- matrix-org sydent
Classification
References
-
github.com
/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da
web, patch, third-party-advisory
-
github.com
/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553
web, patch, third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-29433
advisory
-
github.com
/matrix-org/sydent
package
-
github.com
/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-24.yaml
web
-
pypi.org
/project/matrix-sydent
web
-
pypi.org
/project/matrix-sydent/
package
Sources
- CVE List CVE-2021-29433
- GitHub Advisory GHSA-pw4v-gr34-2553
- NVD CVE-2021-29433
- OSV PYSEC-2021-24
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