CVE-2026-1299
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.
Does this matter?
Lower severity and a low EPSS score (0.57%). Track it; it rarely justifies an emergency change on its own.
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".
- CVSS 4.0
- 6.0 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.57% probability · 47th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-93
- Source
- cna@python.org
EPSS 0.6% 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://cve.org/CVERecord?id=CVE-2024-6923
- https://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413
- https://github.com/python/cpython/commit/0a925ab591c45d6638f37b5e57796f36fa0e56d8
- https://github.com/python/cpython/commit/7877fe424415bc4a13045e62a90a7277413d8cb9
- https://github.com/python/cpython/commit/842ce19a0c0b58d61591e8f6a708c38db1fb94e4
- https://github.com/python/cpython/commit/8cdf6204f4ae821f32993f8fc6bad0d318f95f36
- https://github.com/python/cpython/commit/e417f05ad77a4c30ddc07f99e90fc0cef43e831a
- https://github.com/python/cpython/issues/144125
- https://github.com/python/cpython/pull/144126
- https://mail.python.org/archives/list/security-announce@python.org/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.