CVE-2026-0864: When using the "configparser" module to write configuration files containing multi-line text values with carri

Routine

MEDIUM 5.5UPGRADE

CVE-2026-0864 is a medium-severity flaw (CVSS 5.5) affecting python. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

When 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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 98%)
CISA exploited list	No
Weakness	CWE-74
Published	2026-06-23
Last modified	2026-10-25

Publisher (CNA): Python Software Foundation · Vendor: python

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-23 18:17 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

python python UPGRADE

Affected: < 3.10.21 · >= 3.11.0 and < 3.11.16 · >= 3.12.0 and < 3.12.14 · >= 3.13.0 and < 3.13.15 · >= 3.14.0 and < 3.14.7 · 3.15.0 alpha1 · 3.15.0 alpha2 · 3.15.0 alpha3

Fixed in: 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7

Safe to downgrade to: a release before 3.11.0

1. Check installed version

apt-cache policy python || rpm -q python || python --version

2. UPGRADE to 3.10.21 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade python

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade python

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.11.0 (Debian / Ubuntu)

apt-cache madison python sudo apt install python=<VERSION_BEFORE_3.11.0> sudo apt-mark hold python

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list python sudo dnf downgrade python-<VERSION_BEFORE_3.11.0> sudo dnf versionlock add python

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-0864?

python: upgrade to 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7. Exact commands for each OS are on this page.

Is CVE-2026-0864 being exploited?

CVE-2026-0864 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-0864 affect?

CVE-2026-0864 affects python. Severity is medium (CVSS 5.5). When 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 writt

How urgent is CVE-2026-0864?

Priority 20/100. No elevated risk signals yet.

Software pages

Python vulnerabilities

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References

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