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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".

PUBLISHED Reserved 2026-01-21 | Published 2026-01-23 | Updated 2026-02-11 | Assigner PSF




MEDIUM: 6.0CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-93

Product status

Default status
unaffected

Any version before 3.13.12
affected

3.14.0 (python) before 3.14.3
affected

3.15.0a1 (python) before 3.15.0a6
affected

References

github.com/python/cpython/pull/144126 patch

github.com/python/cpython/issues/144125 issue-tracking

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

mail.python.org/.../thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/ vendor-advisory

github.com/...ommit/052e55e7d44718fe46cbba0ca995cb8fcc359413 patch

github.com/...ommit/0a925ab591c45d6638f37b5e57796f36fa0e56d8 patch

github.com/...ommit/7877fe424415bc4a13045e62a90a7277413d8cb9 patch

github.com/...ommit/842ce19a0c0b58d61591e8f6a708c38db1fb94e4 patch

github.com/...ommit/8cdf6204f4ae821f32993f8fc6bad0d318f95f36 patch

cve.org (CVE-2026-1299)

nvd.nist.gov (CVE-2026-1299)

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