Mishandling of comma during folding and unicode-encoding of email headers
During an address list folding when a separating comma ends up on a folded line and that line is to be unicode-encoded then the separator itself is also unicode-encoded. Expected behavior is that the separating comma remains a plan comma. This can result in the address header being misinterpreted by some mail servers.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Feb 28, 2025
- Updated
- Jul 31, 2026
- EPSS
- 0.6% · 48th percentile
- CWE
- CWE-116
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Report tools
Action score
9
Monitor
Low priority for now.
- CVSS
- 9 / 40 · 2.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · PSF
- 2.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (PSF). Independent of NVD's CPE analysis and usually ahead of it.
Python Software Foundation CPython
- before 3.9.23affected · python
- 3.10.0 and later · before 3.10.17affected · python
- 3.11.0 and later · before 3.11.9affected · python
- 3.12.0 and later · before 3.12.3affected · python
- 3.13.0a1 and later · before 3.13.0a5affected · python
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:11 | pypy3 | before 7.3.5+dfsg-2+deb11u5 | 7.3.5+dfsg-2+deb11u5 |
| Debian:11 | python3.9 | before 3.9.2-1+deb11u3 | 3.9.2-1+deb11u3 |
| Debian:12 | pypy3 | all versions | — |
| Debian:12 | python3.11 | before 3.11.2-6+deb12u6 | 3.11.2-6+deb12u6 |
| Debian:13 | pypy3 | before 7.3.18+dfsg-1 | 7.3.18+dfsg-1 |
| Debian:13 | python3.13 | before 3.13.0~b1-1 | 3.13.0~b1-1 |
| openSUSE:Leap 15.6 | python311-documentation | before 3.11.11-150600.3.21.1 | 3.11.11-150600.3.21.1 |
| openSUSE:Leap 15.6 | python312-documentation | before 3.12.9-150600.3.21.1 | 3.12.9-150600.3.21.1 |
| openSUSE:Tumbleweed | python311 | before 3.11.11-4.1 | 3.11.11-4.1 |
| openSUSE:Tumbleweed | python312 | before 3.12.9-2.1 | 3.12.9-2.1 |
| openSUSE:Tumbleweed | python313 | before 3.13.2-3.1 | 3.13.2-3.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | python311-core | before 3.11.11-150600.3.21.1 | 3.11.11-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | python311-core | before 3.11.11-150600.3.21.1 | 3.11.11-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | python311 | before 3.11.11-150400.9.49.1 | 3.11.11-150400.9.49.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | python311-core | before 3.11.11-150400.9.49.1 | 3.11.11-150400.9.49.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python311 | before 3.11.11-150600.3.21.1 | 3.11.11-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python311 | before 3.11.11-150600.3.21.1 | 3.11.11-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python312 | before 3.12.9-150600.3.21.1 | 3.12.9-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python312 | before 3.12.9-150600.3.21.1 | 3.12.9-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python312-core | before 3.12.9-150600.3.21.1 | 3.12.9-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP6 | python312-core | before 3.12.9-150600.3.21.1 | 3.12.9-150600.3.21.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP7 | python313 | before 3.13.5-150700.4.11.1 | 3.13.5-150700.4.11.1 |
| SUSE:Linux Enterprise Module for Python 3 15 SP7 | python313-core | before 3.13.5-150700.4.11.1 | 3.13.5-150700.4.11.1 |
| SUSE:Linux Micro 6.0 | python311 | before 3.11.11-1.1 | 3.11.11-1.1 |
+3
Same product
python software foundation: all recordsOther highest-scoring records for the same primary product.
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- CVE-2026-3298Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes35Monitor
- CVE-2024-12254Unbounded memory buffering in SelectorSocketTransport.writelines()35Monitor
- CVE-2024-8088Infinite loop when iterating over zip archive entry names from zipfile.Path34Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Python Software Foundation CPython | 3.10.17 | Vendor (CNA) |
| Python Software Foundation CPython | 3.11.9 | Vendor (CNA) |
| Python Software Foundation CPython | 3.12.3 | Vendor (CNA) |
| Python Software Foundation CPython | 3.13.0a5 | Vendor (CNA) |
| Python Software Foundation CPython | 3.9.23 | Vendor (CNA) |
| debian:pypy3 | 7.3.18+dfsg-1 · Debian:13 | Package registry (OSV) |
| debian:python3.11 | 3.11.2-6+deb12u6 · Debian:12 | Package registry (OSV) |
| debian:python3.13 | 3.13.0~b1-1 · Debian:13 | Package registry (OSV) |
| debian:python3.9 | 3.9.2-1+deb11u3 · Debian:11 | Package registry (OSV) |
| opensuse:python311 | 3.11.11-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python311-core | 3.11.11-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python311-documentation | 3.11.11-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python312 | 3.12.9-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python312-core | 3.12.9-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python312-documentation | 3.12.9-150600.3.21.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:python313 | 3.13.2-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| suse:python311 | 3.11.11-150400.9.49.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | Package registry (OSV) |
| suse:python311 | 3.11.11-150600.3.21.1 · SUSE:Linux Enterprise Module for Python 3 15 SP6 | Package registry (OSV) |
| suse:python311-core | 3.11.11-150400.9.49.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | Package registry (OSV) |
| suse:python311-core | 3.11.11-150600.3.21.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP6 | Package registry (OSV) |
| suse:python312 | 3.12.9-150600.3.21.1 · SUSE:Linux Enterprise Module for Python 3 15 SP6 | Package registry (OSV) |
| suse:python312-core | 3.12.9-150600.3.21.1 · SUSE:Linux Enterprise Module for Python 3 15 SP6 | Package registry (OSV) |
| suse:python313 | 3.13.5-150700.4.11.1 · SUSE:Linux Enterprise Module for Python 3 15 SP7 | Package registry (OSV) |
| suse:python313-core | 3.13.5-150700.4.11.1 · SUSE:Linux Enterprise Module for Python 3 15 SP7 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-116 · Improper Encoding or Escaping of OutputCVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/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-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/python/cpython/commit/09fab93c3d857496c0bd162797fab816c311ee48
- github.com/python/cpython/commit/70754d21c288535e86070ca7a6e90dcb670b8593
- github.com/python/cpython/commit/9148b77e0af91cdacaa7fe3dfac09635c3fe9a74
- github.com/python/cpython/commit/a4ef689ce670684ec132204b1cd03720c8e0a03d
- github.com/python/cpython/commit/d4df3c55e4c5513947f907f24766b34d2ae8c090
- github.com/python/cpython/issues/100884
- github.com/python/cpython/pull/100885
- github.com/python/cpython/pull/119099
- mail.python.org/archives/list/security-announce@python.org/thread/MB62IZMEC3UM6SGHP5LET5JX2Y7H4ZUR/
- lists.debian.org/debian-lts-announce/2025/03/msg00013.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.