Configuration Injection via Carriage Return (\r) in write() method

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-0864
StatePUBLISHED
AssignerPSF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-23 18:17:41 UTC
Updated2026-06-25 19:51:26 UTC
DescriptionWhen using the "configparser" module to write configuration files containing multi-line text values with carriage return characters (\r) the resulting file could be injected with unexpected keys and values if the attacker controls the written value.

Risk And Classification

Primary CVSS: v4.0 4.1 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:P/VC:N/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

EPSS: 0.001280000 probability, percentile 0.027660000 (date 2026-06-29)

Problem Types: CWE-74 | CWE-74 CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary4.1MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS4.1MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
High
User Interaction
Passive
Confidentiality
None
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:P/VC:N/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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Python Software Foundation CPython affected 3.15.0 python Not specified

References

ReferenceSourceLinkTags
github.com/python/cpython/commit/0adb386f6e68eb2e73d32e19f235d012df009528 [email protected] github.com
github.com/python/cpython/commit/5858e42c539dac8394636a6e9b30472b8994851f [email protected] github.com
github.com/python/cpython/commit/71f2e02a52d47417a6fd69f456346cd8aa7aca98 [email protected] github.com
mail.python.org/archives/list/[email protected]/thread/CV4NE6AFCRJ... [email protected] mail.python.org
github.com/python/cpython/pull/151559 [email protected] github.com
github.com/python/cpython/commit/aaf850fd333cd89e9aada03d92aaa788a6cb1bb8 [email protected] github.com
github.com/python/cpython/issues/143927 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: D0n9 (https://github.com/D0n9) (en)

CNA: Petr Viktorin (https://github.com/encukou) (en)

CNA: Seth Larson (https://github.com/sethmlarson) (en)

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