CVE-2026-1299
email BytesGenerator header injection due to unquoted newlines
At a glance
- Severity
- MEDIUM 6.0
- EPSS
- EPSS 0.57 % · percentile 47 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- PSF
- NVD status
- Deferred
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".
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.0 | 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 | PSF |
| CVSS 4.0 | MEDIUM 6.0 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cna@python.org (Secondary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2026-4272
- GCVE · GCVE-0-2026-1299
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0556 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0394 — Multiples vulnérabilités dans VMware Tanzu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0327 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0326 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0316 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0315 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0086 — Vulnérabilité dans CPython · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Python Software Foundation · CPython | affected 0 < 3.10.20 ; affected 3.11.0 < 3.11.15 ; affected 3.12.0 < 3.12.13 ; affected 3.13.0 < 3.13.12 ; affected 3.14.0 < 3.14.3 ; affected 3.15.0a1 < 3.15.0a6 |
References
- https://github.com/python/cpython/pull/144126
- https://github.com/python/cpython/issues/144125
- https://cve.org/CVERecord?id=CVE-2024-6923
- https://mail.python.org/archives/list/security-announce@python.org/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/
- 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
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |