CVE Tools
Sign in

CVE-2021-29433

Denial of service (via resource exhaustion) due to improper input validation

Published: Apr 15, 2021Updated: Nov 21, 2024 Sources: CVE List NVD GHSACWE-20
4.3MEDIUM
NVD MITRE
EPSS Score
0.9%
Top 42.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

CWE-20CWE-400

Affected Products

matrix
oss-project·GBaka matrix irc bridge, synapse, javascript sdk
sydentOn-prem
Communications / messaging-chat
matrix-org
oss-project·DEaka synapse, matrix-js-sdk, matrix appservice irc
sydent
Communications / messaging-chat
PyPI
package-ecosystem
matrix-sydent
OSS Libraries

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Impact
Initial Access
View detailed technique mapping

References

https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da
github.com
https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553
github.com
https://nvd.nist.gov/vuln/detail/CVE-2021-29433
nvd.nist.gov
and 3 more references View all →

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2021-29433 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows