CVE-2021-21274
MEDIUM4.3EPSS 0.45%Denial of service attack via .well-known lookups
發布日:2021/3/1修改日:2026/3/13
描述
### Impact 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. ### Patches Issue is resolved by #8950. A bug not affecting the security aspects of this was fixed in #9108. ### Workarounds The `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation.
受影響套件(3)
- Debian/matrix-synapsefrom 0, < 1.25.0-1
- PyPI/matrix-synapse>= 0.99.0, < 1.25.0
- PyPI/matrix-synapsefrom 0, < ff5c4da1289cb5e097902b3e55b771be342c29d6 | >= 0.99.0, < 1.25.0
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L |
參考連結(9)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-21274
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-21274
- PATCHhttps://github.com/matrix-org/synapse
- WEBhttps://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6
- WEBhttps://github.com/matrix-org/synapse/pull/8950
- WEBhttps://github.com/matrix-org/synapse/releases/tag/v1.25.0
- WEBhttps://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8
- WEBhttps://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-132.yaml
- WEBhttps://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY