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".
CVE-2026-1299
This medium-severity CVE scores 6.0 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 83% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.0
- EG Score
- 6.0(medium)
- EPSS
- 42.8%
- KEV
- Not listed
Published
January 23, 2026
Last Modified
April 15, 2026
References (10)
- cna@pythonhttps://cve.org/CVERecord?id=CVE-2024-6923
- cna@pythonhttps://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413
- cna@pythonhttps://github.com/python/cpython/commit/0a925ab591c45d6638f37b5e57796f36fa0e56d8
- cna@pythonhttps://github.com/python/cpython/commit/7877fe424415bc4a13045e62a90a7277413d8cb9
- cna@pythonhttps://github.com/python/cpython/commit/842ce19a0c0b58d61591e8f6a708c38db1fb94e4
- cna@pythonhttps://github.com/python/cpython/commit/8cdf6204f4ae821f32993f8fc6bad0d318f95f36
- cna@pythonhttps://github.com/python/cpython/commit/e417f05ad77a4c30ddc07f99e90fc0cef43e831a
- cna@pythonhttps://github.com/python/cpython/issues/144125
- cna@pythonhttps://github.com/python/cpython/pull/144126
- cna@pythonhttps://mail.python.org/archives/list/[email protected]/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/
Vendor Advisories for CVE-2026-1299(20)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:16174Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server 3.3.3 (Spyre)
- RHSA-2026:8824Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:8822Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:8748Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server Model Optimization Tools 3.3.1 (CUDA)
- RHSA-2026:8746Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server 3.3.1 (CUDA)
- RHSA-2026:8747Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server 3.3.1 (ROCm)
- RHSA-2026:7661Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7443Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- +12 more
Patch Availability(30)
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(13)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
- Red HatRHSA-2026:2128MODERATE2026-01-23
RHSA-2026:2128 — Moderate
- Red HatRHSA-2026:4165MODERATE2026-01-23
RHSA-2026:4165 — Moderate
- Red HatRHSA-2026:4168MODERATE2026-01-23
RHSA-2026:4168 — Moderate
- Red HatRHSA-2026:4216MODERATE2026-01-23
RHSA-2026:4216 — Moderate
- Red HatRHSA-2026:4463MODERATE2026-01-23
RHSA-2026:4463 — Moderate
- Red HatRHSA-2026:4473MODERATE2026-01-23
RHSA-2026:4473 — Moderate
- Red HatRHSA-2026:4713MODERATE2026-01-23
RHSA-2026:4713 — Moderate
- Red HatRHSA-2026:4746MODERATE2026-01-23
RHSA-2026:4746 — Moderate
- Red HatRHSA-2026:4943MODERATE2026-01-23
RHSA-2026:4943 — Moderate
- Red HatRHSA-2026:5152MODERATE2026-01-23
RHSA-2026:5152 — Moderate
- Red HatRHSA-2026:5216MODERATE2026-01-23
RHSA-2026:5216 — Moderate
- Red HatRHSA-2026:5221MODERATE2026-01-23
RHSA-2026:5221 — Moderate
- Red HatRHSA-2026:5223MODERATE2026-01-23
RHSA-2026:5223 — Moderate
Data Freshness Timeline
(refreshed 9× in last 7d / 39× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-16 17:02 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-13 22:30 UTCEPSS rescore
- 2026-07-13 15:07 UTCOSV refresh
- 2026-07-13 06:12 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
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- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 12:31 UTCOSV refresh
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-23 21:32 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-17 17:53 UTCEPSS rescore
- 2026-06-16 17:52 UTCEPSS rescore
- 2026-06-15 17:48 UTCEPSS rescore
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 03:28 UTCEG score recompute▲ 6.00
- 2026-06-08 03:28 UTCVendor advisory
- 2026-06-08 03:28 UTCGHSA enrichment
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-05 22:47 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-02 20:13 UTCEPSS rescore
- 2026-06-02 20:13 UTCEPSS rescore
- 2026-06-01 16:57 UTCOSV refresh
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-29 13:44 UTCEPSS rescore
- 2026-05-29 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-26 13:44 UTCEPSS rescore
- 2026-05-26 13:44 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-22 21:16 UTCEPSS rescore
- 2026-05-21 22:43 UTCEPSS rescore
- 2026-05-21 00:08 UTCEG score recompute
- 2026-05-21 00:08 UTCVendor advisory
- 2026-05-21 00:08 UTCGHSA enrichment
- 2026-05-20 22:38 UTCEPSS rescore
- 2026-05-20 22:37 UTCEPSS rescore
- 2026-05-20 22:37 UTCEPSS rescore
- 2026-05-20 11:22 UTCEPSS rescore
- 2026-05-20 11:21 UTCEPSS rescore
- 2026-05-20 11:21 UTCEPSS rescore
- 2026-05-18 21:31 UTCEPSS rescore
Frequently asked(5)
What is CVE-2026-1299?
When was CVE-2026-1299 disclosed?
Is CVE-2026-1299 actively exploited?
What is the CVSS score of CVE-2026-1299?
How do I remediate CVE-2026-1299?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-1299
Is Your Infrastructure Affected by CVE-2026-1299?
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