NVD Vulnerability Detail

CVE-2021-21274

Summary	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 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation.
Publication Date	Feb. 27, 2021, 3:15 a.m.
Registration Date	Feb. 27, 2021, 10:02 a.m.
Last Update	Nov. 21, 2024, 2:47 p.m.

Affected software configurations

Configuration1		or higher	or less	more than	less than
cpe:2.3:a:matrix:synapse::::::::		0.99.0			1.25.0

Configuration2		or higher	or less	more than	less than
cpe:2.3:o:fedoraproject:fedora:34:::::::*

Related information, measures and tools

No	URL	タグ
1	https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6	Patch Third Party Advisory
2	https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6	Patch Third Party Advisory
3	https://github.com/matrix-org/synapse/pull/8950	Patch Third Party Advisory
4	https://github.com/matrix-org/synapse/pull/8950	Patch Third Party Advisory
5	https://github.com/matrix-org/synapse/releases/tag/v1.25.0	Third Party Advisory
6	https://github.com/matrix-org/synapse/releases/tag/v1.25.0	Third Party Advisory
7	https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8	Patch Third Party Advisory
8	https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8	Patch Third Party Advisory
9	https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/
10	https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/

Common Vulnerabilities List

No	CWE	Name	URL
1	CWE-770	制限またはスロットリング無しのリソースの割り当て	https://cwe.mitre.org/data/definitions/770.html

JVN Vulnerability Information

Synapse におけるリソースの枯渇に関する脆弱性

Title	Synapse におけるリソースの枯渇に関する脆弱性
Summary	Synapse には、リソースの枯渇に関する脆弱性が存在します。
Possible impacts	サービス運用妨害 (DoS) 状態にされる可能性があります。
Solution	ベンダより正式な対策が公開されています。ベンダ情報を参照して適切な対策を実施してください。
Publication Date	Jan. 13, 2021, midnight
Registration Date	Nov. 17, 2021, 4:28 p.m.
Last Update	Nov. 17, 2021, 4:28 p.m.

Affected System

Matrix

Synapse 1.25.0 未満

CVE (情報セキュリティ共通脆弱性識別子)

No	Name	URL
Common Vulnerabilities and Exposures (CVE)
1	CVE-2021-21274	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21274
National Vulnerability Database (NVD)
2	CVE-2021-21274	https://nvd.nist.gov/vuln/detail/CVE-2021-21274

CWE (共通脆弱性タイプ一覧)

No	Name	URL
JVNDB
1	CWE-400	https://cwe.mitre.org/data/definitions/400.html

ベンダー情報

No	Name	URL
GitHub
1	Add a maximum size for well-known lookups. #8950	https://github.com/matrix-org/synapse/pull/8950
2	Add a maximum size for well-known lookups. (#8950)	https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6
3	Denial of service attack via .well-known lookups	https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8
4	v1.25.0	https://github.com/matrix-org/synapse/releases/tag/v1.25.0

Change Log

No	Changed Details	Date of change
1	[2021年11月17日] 掲載	Nov. 17, 2021, 4:28 p.m.