| Name | CVE-2020-7212 |
| Description | The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| python-urllib3 (PTS) | bullseye | 1.26.5-1~exp1 | fixed |
| bullseye (security) | 1.26.5-1~exp1+deb11u1 | fixed | |
| bookworm | 1.26.12-1 | fixed | |
| sid, trixie | 2.2.3-4 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| python-urllib3 | source | jessie | (not affected) | |||
| python-urllib3 | source | stretch | (not affected) | |||
| python-urllib3 | source | buster | (not affected) | |||
| python-urllib3 | source | (unstable) | 1.25.8-1 |
[buster] - python-urllib3 <not-affected> (Vulnerable code introduced later)
[stretch] - python-urllib3 <not-affected> (Vulnerable code introduced later)
[jessie] - python-urllib3 <not-affected> (Vulnerable code introduced later)
https://github.com/urllib3/urllib3/pull/1787
Introduced by: https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e0221a (1.25.2)
Fixed by: https://github.com/urllib3/urllib3/commit/a2697e7c6b275f05879b60f593c5854a816489f0 (1.25.8)