CVE-2025-45165.9MediumCWE-416

CVE-2025-4516: Use-after-free in "unicode_escape" decoder with error handler

Python Software Foundation · CPython

Vendor fix available · Affected: Python Software Foundation CPython · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.2%probability of exploitation in the next 30 days

13th percentile

050100

Higher than 13% of scored CVEs

5.9MediumCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

There is an issue in CPython when using `bytes.decode("unicode_escape", error="ignore|replace")`. If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

Python Software Foundation · CPythonbefore 3.9.23; from 3.10.0 before 3.10.18; from 3.11.0 before 3.11.13; from 3.12.0 before 3.12.11; from 3.13.0 before 3.13.4; from 3.14.0a1 before 3.14.0b2

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Use After Free · Memory Corruption
Vendor: Python Software Foundation
Published: May 2025
Band: Unlikely (under 1%), May 2025

CoverageNo articles yet

No CyberSIXT article names CVE-2025-4516 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.