CVE-2021-21393
published 2021-04-12CVE-2021-21393: Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP…
PriorityP336medium6.5CVSS 3.1
AVNACLPRLUINSUCNINAH
EPSS
1.60%
73.0th percentile
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 Synapse is missing 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. Note that the groups feature is not part of the Matrix specification and the chosen maximum lengths are arbitrary. Not all clients might abide by them. Refer to referenced GitHub security advisory for additional details including workarounds.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | matrix-synapse | < matrix-synapse 1.28.0-1 (forky) | matrix-synapse 1.28.0-1 (forky) |
| fedoraproject | fedora | — | — |
| matrix-org | synapse | < 1.28.0 | 1.28.0 |
| matrix | synapse | < 1.28.0 | 1.28.0 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvdv2.04.3MEDIUMAV:N/AC:M/Au:N/C:N/I:N/A:P
osv6.5MEDIUM
vendor_debian5.3MEDIUM
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OSV
Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
osv·2021-04-13
CVE-2021-21393 [MEDIUM] Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
### Impact
Missing input validation of some parameters on the groups (also known as communities) endpoints could cause excessive use of disk space and memory leading to resource exhaustion. Additionally clients may have issues rendering large fields.
### Patches
This issue is fixed by #9321 and #9393.
### Workarounds
The groups feature can be disabled (by setting `enable_group_creation` to `False`) to mitigate this issue. Note that it is disabled by default.
### Other information
Note that the groups feature is not part of the [Matrix specification](https://matrix.org/docs/spec/) and the chosen maximum lengths are arbitrary. Not all clients might abide by them.
GHSA
Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
ghsa·2021-04-13
CVE-2021-21393 [MEDIUM] CWE-20 Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
### Impact
Missing input validation of some parameters on the groups (also known as communities) endpoints could cause excessive use of disk space and memory leading to resource exhaustion. Additionally clients may have issues rendering large fields.
### Patches
This issue is fixed by #9321 and #9393.
### Workarounds
The groups feature can be disabled (by setting `enable_group_creation` to `False`) to mitigate this issue. Note that it is disabled by default.
### Other information
Note that the groups feature is not part of the [Matrix specification](https://matrix.org/docs/spec/) and the chosen maximum lengths are arbitrary. Not all clients might abide by them.
OSV
CVE-2021-21393: Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse)
osv·2021-04-12·CVSS 6.5
CVE-2021-21393 [MEDIUM] CVE-2021-21393: Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse)
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 Synapse is missing 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. Note that the groups feature is not part of the Matrix specification and the chosen maximum lengths are arbitrary. Not all clients might abide by them. Refer to referenced GitHub security advisory for additional details including workarounds.
Debian
CVE-2021-21393: matrix-synapse - Synapse is a Matrix reference homeserver written in python (pypi package matrix-...
vendor_debian·2021·CVSS 5.3
CVE-2021-21393 [MEDIUM] CVE-2021-21393: matrix-synapse - Synapse is a Matrix reference homeserver written in python (pypi package matrix-...
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 Synapse is missing 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. Note that the groups feature is not part of the Matrix specification and the chosen maximum lengths are arbitrary. Not all clients might abide by them. Refer to referenced GitHub security advisory for additional details including workarounds.
Scope: local
forky: resolved (fixed in 1.28.0-1)
sid: resolved (fixed in 1.28.0-1)
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://github.com/matrix-org/synapse/pull/9321https://github.com/matrix-org/synapse/pull/9393https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/https://pypi.org/project/matrix-synapse/https://github.com/matrix-org/synapse/pull/9321https://github.com/matrix-org/synapse/pull/9393https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/https://pypi.org/project/matrix-synapse/
2021-04-12
Published