CVE-2020-5236
Catastrophic backtracking in regex allows Denial of Service in Waitress
描述
Waitress version 1.4.2 allows a DOS attack When waitress receives a header that contains invalid characters. When a header like "Bad-header: xxxxxxxxxxxxxxx\x10" is received, it will cause the regular expression engine to catastrophically backtrack causing the process to use 100% CPU time and blocking any other interactions. This allows an attacker to send a single request with an invalid header and take the service offline. This issue was introduced in version 1.4.2 when the regular expression was updated to attempt to match the behaviour required by errata associated with RFC7230. The regular expression that is used to validate incoming headers has been updated in version 1.4.3, it is recommended that people upgrade to the new version of Waitress as soon as possible.
如何修補 CVE-2020-5236
要修補 CVE-2020-5236,請將受影響套件升級到下列已修補版本。
- —升級至 1.4.3 或更新版本
- —升級至 6e46f9e3f014d64dd7d1e258eaf626e39870ee1f 或更新版本
CVE-2020-5236 正在被利用嗎?
低 — EPSS 為 2.6%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- >= 1.4.2, < 1.4.3
- from 0, < 6e46f9e3f014d64dd7d1e258eaf626e39870ee1f | from 0, < 1.4.3
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:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM5.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H |