CVE-2026-1299

medium

Description

The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing headers that don't respect email folding rules, the new behavior will reject the incorrectly folded headers in "BytesGenerator".

References

https://mail.python.org/archives/list/[email protected]/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/

https://github.com/python/cpython/pull/144126

https://github.com/python/cpython/issues/144125

https://github.com/python/cpython/commit/e417f05ad77a4c30ddc07f99e90fc0cef43e831a

https://github.com/python/cpython/commit/8cdf6204f4ae821f32993f8fc6bad0d318f95f36

https://github.com/python/cpython/commit/842ce19a0c0b58d61591e8f6a708c38db1fb94e4

https://github.com/python/cpython/commit/7877fe424415bc4a13045e62a90a7277413d8cb9

https://github.com/python/cpython/commit/0a925ab591c45d6638f37b5e57796f36fa0e56d8

https://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413

https://cve.org/CVERecord?id=CVE-2024-6923

Details

Source: Mitre, NVD

Published: 2026-01-23

Updated: 2026-02-13

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:C/A:N

Severity: High

CVSS v3

Base Score: 7.1

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

Severity: High

CVSS v4

Base Score: 6

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00017