What is the CVSS score of CVE-2025-12781?

CVE-2025-12781 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Python are affected by CVE-2025-12781?

CVE-2025-12781 presents moderate security risk rated CVSS 5.3. Exploitation could compromise the security of affected deployments. Proof-of-concept code is publicly available.. A patch is available.

Is there a public PoC exploit available for CVE-2025-12781?

Yes, a public proof-of-concept exploit is available for CVE-2025-12781. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2025-12781?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Python CVE-2025-12781

MEDIUM

Incorrect Type Conversion or Cast (CWE-704)

2026-01-21 cna@python.org

Python Red Hat Suse

5.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

SUSE

MEDIUM

qualitative

Red Hat

5.3 MEDIUM

qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Feb 02, 2026 - 17:25 vuln.today

Public exploit code

Patch released

Feb 02, 2026 - 17:25 nvd

Patch available

CVE Published

Jan 21, 2026 - 20:16 nvd

MEDIUM 5.3

DescriptionCVE.org

When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode() functions in the "base64" module the characters "+/" will always be accepted, regardless of the value of "altchars" parameter, typically used to establish an "alternative base64 alphabet" such as the URL safe alphabet. This behavior matches what is recommended in earlier base64 RFCs, but newer RFCs now recommend either dropping characters outside the specified base64 alphabet or raising an error. The old behavior has the possibility of causing data integrity issues.

This behavior can only be insecure if your application uses an alternate base64 alphabet (without "+/"). If your application does not use the "altchars" parameter or the urlsafe_b64decode() function, then your application does not use an alternative base64 alphabet.

The attached patches DOES NOT make the base64-decode behavior raise an error, as this would be a change in behavior and break existing programs. Instead, the patch deprecates the behavior which will be replaced with the newly recommended behavior in a future version of Python. Users are recommended to mitigate by verifying user-controlled inputs match the base64 alphabet they are expecting or verify that their application would not be affected if the b64decode() functions accepted "+" or "/" outside of altchars.

AnalysisAI

Technical ContextAI

Classified as CWE-704 (Incorrect Type Conversion or Cast). Affects Python. When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode() functions in the "base64" module the characters "+/" will always be accepted, regardless of the value of "altchars" parameter, typically used to establish an "alternative base64 alphabet" such as the URL safe alphabet. This behavior matches what is recommended in earlier base64 RFCs, but newer RFCs now recommend either dropping characters outside the specified base64 alphabet or raising an error. The old behavior

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

More in Python

View all

CVE-2025-24016 CRITICAL Act Now POC

9.9 Feb 10

Wazuh SIEM platform versions 4.4.0 through 4.9.0 contain an unsafe deserialization vulnerability in the DistributedAPI t

CVE-2025-27520 CRITICAL Act Now POC

9.8 Apr 04

BentoML version 1.4.2 and earlier contains an unauthenticated remote code execution vulnerability through insecure deser

CVE-2025-2945 CRITICAL Act Now POC

9.9 Apr 03

pgAdmin 4 contains critical remote code execution vulnerabilities in the Query Tool download and Cloud Deployment endpoi

CVE-2013-5093 MEDIUM This Month POC

6.8 Sep 27

The renderLocalView function in render/views.py in graphite-web in Graphite 0.9.5 through 0.9.10 uses the pickle Python

CVE-2025-32375 CRITICAL Act Now POC

9.8 Apr 09

BentoML is a Python library for building online serving systems optimized for AI apps and model inference. Rated critica

CVE-2014-0224 HIGH Act Now POC

7.4 Jun 05

OpenSSL before 0.9.8za, 1.0.0 before 1.0.0m, and 1.0.1 before 1.0.1h does not properly restrict processing of ChangeCiph

CVE-2024-21644 HIGH Act Now POC

7.5 Jan 08

pyLoad download manager version prior to 0.5.0b3.dev77 exposes the Flask SECRET_KEY through an unauthenticated endpoint.

CVE-2026-33017 CRITICAL Act Now POC

9.3 Mar 17

Langflow (a visual LLM pipeline builder) contains a critical unauthenticated code execution vulnerability (CVE-2026-3301

CVE-2017-9462 HIGH Act Now POC

8.8 Jun 06

In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and conse

CVE-2026-49869 CRITICAL Act Now POC

10.0 Jun 26

Unauthenticated remote code execution affects Kestra OSS (the open-source event-driven orchestration platform) prior to

CVE-2026-39987 CRITICAL Act Now POC

9.3 Apr 08

Unauthenticated remote code execution in Marimo ≤0.20.4 allows attackers to execute arbitrary system commands via the `/

CVE-2024-21645 MEDIUM This Month POC

5.3 Jan 08

pyLoad is the free and open-source Download Manager written in pure Python. Rated medium severity (CVSS 5.3), this vulne

Same weakness CWE-704 – Incorrect Type Conversion or Cast

View all

CVE-2017-3106 HIGH POC

8.8

CVE-2025-41646 CRITICAL POC

9.8

CVE-2026-15826 CRITICAL POC

9.8

CVE-2018-14403 CRITICAL POC

9.8

CVE-2021-28918 CRITICAL POC

9.1

CVE-2021-39173 HIGH POC

8.8

CVE-2018-6064 HIGH POC

8.8

CVE-2018-3843 HIGH POC

8.8

Vendor StatusVendor

SUSE

Severity: Medium

Product	Status
Container suse/sl-micro/6.0/toolbox:13.2-9.73	Affected
Container suse/sl-micro/6.1/baremetal-os-container:2.2.1-7.67 Image SL-Micro-EC2 Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd	Affected
Image SLES15-SP4-HPC-BYOS Image SLES15-SP4-HPC-BYOS-EC2 Image SLES15-SP4-HPC-EC2 Image SLES15-SP4-Hardened-BYOS Image SLES15-SP4-Hardened-BYOS-EC2 Image SLES15-SP4-SAP-BYOS Image SLES15-SP4-SAP-BYOS-EC2 Image SLES15-SP4-SAP-Hardened-BYOS Image SLES15-SP4-SAP-Hardened-BYOS-EC2 Image SLES15-SP5-BYOS-EC2 Image SLES15-SP5-HPC-BYOS-EC2 Image SLES15-SP5-Hardened-BYOS-EC2 Image SLES15-SP5-SAP-BYOS-EC2 Image SLES15-SP5-SAP-Hardened-BYOS-EC2	Affected
Image SLES15-SP7-SAP-BYOS-EC2 Image SLES15-SP7-SAP-Hardened-BYOS-EC2	Affected
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise High Performance Computing 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7	Fixed

CVE-2025-12781 vulnerability details – vuln.today

Back

Python CVE-2025-12781

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

More in Python

Same weakness CWE-704 – Incorrect Type Conversion or Cast

Vendor StatusVendor

SUSE

Share

External POC / Exploit Code