CVE-2026-1299
published 2026-01-23CVE-2026-1299: The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for…
PriorityP336medium6CVSS 4.0
AVNACLATPPRLUINVCLVIHVANSCNSINSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.56%
42.8th percentile
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".
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | pypy3 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.11 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.13 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.14 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.9 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| python_software_foundation | cpython | < 3.10.20 | 3.10.20 |
| python_software_foundation | cpython | >= 3.11.0 < 3.11.15 | 3.11.15 |
| python_software_foundation | cpython | >= 3.12.0 < 3.12.13 | 3.12.13 |
| python_software_foundation | cpython | >= 3.13.0 < 3.13.12 | 3.13.12 |
| python_software_foundation | cpython | >= 3.14.0 < 3.14.3 | 3.14.3 |
| python_software_foundation | cpython | >= 3.15.0a1 < 3.15.0a6 | 3.15.0a6 |
| ubuntu | python3.10 | — | — |
| ubuntu | python3.12 | — | — |
| ubuntu | python3.14 | — | — |
CVSS provenance
nvdv4.06.0MEDIUMCVSS: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
osv6.0MEDIUM
vendor_debian6.0MEDIUM
vendor_redhat6.0MEDIUM
vendor_ubuntu3.3LOW
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Ubuntu
Python vulnerabilities
vendor_ubuntu·2026-07-06·CVSS 3.3
CVE-2026-9669 [LOW] Python vulnerabilities
Title: Python vulnerabilities
Summary: Several security issues were fixed in Python.
It was discovered that Python incorrectly normalized paths in the tarfile
module. An attacker could possibly use this issue to bypass path
restrictions. This issue only affected Ubuntu 22.04 LTS and Ubuntu 24.04
LTS. (CVE-2025-13462)
It was discovered that Python's HTMLParser incorrectly handled certain
malformed HTML input. An attacker could possibly use this issue to cause
Python to crash, resulting in a denial of service. This issue only affected
Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2025-69534)
It was discovered that Python's email module incorrectly quoted newlines
in headers. An attacker could possibly use this issue to inject arbitrary
email headers. This issue only affected Ubuntu 22.04 L
Red Hat
cpython: email header injection due to unquoted newlines
vendor_redhat·2026-01-23·CVSS 6.0
CVE-2026-1299 [MEDIUM] CWE-93 cpython: email header injection due to unquoted newlines
cpython: email header injection due to unquoted newlines
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".
A flaw was found in the email module in the Python standard library. When serializing an email message, the BytesGenerator class fails to properly quote newline characters for email headers. This issue is exploitable when the LiteralHeader class is used as it does not respect email folding rules, allowing an attacker to inject email headers and potenti
Debian
CVE-2026-1299: pypy3 - The email module, specifically the "BytesGenerator" class, didn’t properly quot...
vendor_debian·2026·CVSS 6.0
CVE-2026-1299 [MEDIUM] CVE-2026-1299: pypy3 - The email module, specifically the "BytesGenerator" class, didn’t properly quot...
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".
Scope: local
bookworm: open
bullseye: open
forky: open
sid: open
trixie: open
GHSA
GHSA-jh94-8q48-f3m3: The
email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when
serializing an email message allowing
ghsa_unreviewed·2026-01-23
CVE-2026-1299 [MEDIUM] CWE-93 GHSA-jh94-8q48-f3m3: The
email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when
serializing an email message allowing
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".
OSV
CVE-2026-1299: The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing
osv·2026-01-23·CVSS 6.0
CVE-2026-1299 [MEDIUM] CVE-2026-1299: The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing
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".
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-1299 asahi-installer: email header injection due to unquoted newlines [fedora-42]
bugzilla·2026-01-28·CVSS 6.0
CVE-2026-1299 [MEDIUM] CVE-2026-1299 asahi-installer: email header injection due to unquoted newlines [fedora-42]
CVE-2026-1299 asahi-installer: email header injection due to unquoted newlines [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '42'.
Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change
Bugzilla
CVE-2026-1299 cpython: email header injection due to unquoted newlines
bugzilla·2026-01-23·CVSS 6.0
CVE-2026-1299 [MEDIUM] CVE-2026-1299 cpython: email header injection due to unquoted newlines
CVE-2026-1299 cpython: email header injection due to unquoted newlines
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".
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:2128 https://access.redhat.com/errata/RHSA-2026:2128
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:4165 https://access.redhat.com/errata/RHSA-2026:4165
---
This issu
Wiz
CVE-2026-1299 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 6.0
CVE-2026-1299 [MEDIUM] CVE-2026-1299 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-1299 :
Rocky Linux vulnerability analysis and mitigation
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".
Source : NVD
## 6
Score
Published January 23, 2026
Severity MEDIUM
CNA Score 6.0
Affected Technologies
Rocky Linux
Python Interpreter
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 13.5
Exploitation Probability (EPSS) N/A
Affected pac
https://cve.org/CVERecord?id=CVE-2024-6923https://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413https://github.com/python/cpython/commit/0a925ab591c45d6638f37b5e57796f36fa0e56d8https://github.com/python/cpython/commit/7877fe424415bc4a13045e62a90a7277413d8cb9https://github.com/python/cpython/commit/842ce19a0c0b58d61591e8f6a708c38db1fb94e4https://github.com/python/cpython/commit/8cdf6204f4ae821f32993f8fc6bad0d318f95f36https://github.com/python/cpython/commit/e417f05ad77a4c30ddc07f99e90fc0cef43e831ahttps://github.com/python/cpython/issues/144125https://github.com/python/cpython/pull/144126https://mail.python.org/archives/list/[email protected]/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/
2026-01-23
Published