CVE-2020-26137
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().
Does this matter?
Lower severity and a low EPSS score (2.27%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 2.27% probability · 83th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-74
- Affected
- python/urllib3 · canonical/ubuntu linux · debian/debian linux · oracle/communications cloud native core network function cloud native environment · oracle/zfs storage appliance kit
- Source
- cve@mitre.org
EPSS 2.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugs.python.org/issue39603Issue Tracking, Vendor Advisory
- https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436bPatch, Third Party Advisory
- https://github.com/urllib3/urllib3/pull/1800Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00015.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
- https://usn.ubuntu.com/4570-1/Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
- https://bugs.python.org/issue39603Issue Tracking, Vendor Advisory
- https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436bPatch, Third Party Advisory
- https://github.com/urllib3/urllib3/pull/1800Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00015.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
- https://usn.ubuntu.com/4570-1/Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.