Medium severity · published Jan 20, 2026
CVE-2026-0865
wsgiref.headers.Headers allows header newline injection
5.9
CVSS
0.6%
EPSS
No
On KEV
Description
User-controlled header names and values containing newlines can allow injecting HTTP headers.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CP
CPython · Python Software Foundation
before 3.10.20; 3.11.0 before 3.11.15; 3.12.0 before 3.12.13; 3.13.0 before 3.13.12; 3.14.0 before 3.14.3; 3.15.0a1 before 3.15.0a6 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-0865
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-0865
github.com
https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58
github.com
https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510
github.com
https://github.com/python/cpython/commit/286e3ac39984fe85a17f4ab39c64d382137aae5f
github.com
https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2
github.com
https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5
github.com
https://github.com/python/cpython/commit/66da7bf6fe7b81e3ecc9c0a25bd47d4616c8d1a6
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