GHSA-wqvq-5m8c-6g24 CVE-2020-26137 PYSEC-2020-148
CRLF injection in urllib3
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 2.27%
- Chance of exploitation in the next 30 days. Higher than 83.05% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
- Fix
1.25.9- Upgrade urllib3 to this version or later
Description
urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
Affected versions
PyPI
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
urllib3 PyPI → 1.25.9
- pip
pip install --upgrade "urllib3>=1.25.9"- poetry
poetry add "urllib3>=1.25.9"- uv
uv add "urllib3>=1.25.9"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
How to prevent it
- Requirements: Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Implementation: Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.
References
Advisories
Packages
Other links
- github.com/urllib3/urllib3/pull/1800
- github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436b
- bugs.python.org/issue39603
- github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2020-148.yaml
- lists.debian.org/debian-lts-announce/2021/06/msg00015.html
- lists.debian.org/debian-lts-announce/2023/10/msg00012.html
- usn.ubuntu.com/4570-1
- oracle.com/security-alerts/cpujul2022.html
- oracle.com/security-alerts/cpuoct2021.html
- usn.ubuntu.com/4570-1
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-vxq7-64xx-v4gw urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory | High | Also affects urllib3 |
| GHSA-gh4c-6fx4-qh6g urllib3: Chunked Deflate streaming can enter an infinite loop | Medium | Also affects urllib3 |
| GHSA-8988-9cw3-xx77 urllib3: HTTPS proxy TLS configuration may be ignored or overridden | High | Also affects urllib3 |
| GHSA-mf9v-mfxr-j63j urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API | High | Also affects urllib3 |
| GHSA-qccp-gfcp-xxvc urllib3: Sensitive headers forwarded across origins in proxied low-level redirects | High | Also affects urllib3 |
| GHSA-38jv-5279-wg99 Decompression-bomb safeguards bypassed when following HTTP redirects (streaming API) | High | Also affects urllib3 |
| GHSA-2xpw-w6gg-jr37 urllib3 streaming API improperly handles highly compressed data | High | Also affects urllib3 |
| GHSA-gm62-xv2j-4w53 urllib3 allows an unbounded number of links in the decompression chain | High | Also affects urllib3 |
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