# CVE-2026-3446: Base64 decoding stops at first padded quad by default > Base64 decoding stops early on padded quads, potentially allowing data acceptance discrepancies with other implementations unless strict validation is enabled. - **Severity:** Medium 6.0 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 10 Apr 2026 - **Updated:** 13 Apr 2026 - **Also known as:** BELL-CVE-2026-3446, BIT-libpython-2026-3446, BIT-python-2026-3446, BIT-python-min-2026-3446, DEBIAN-CVE-2026-3446, ECHO-9eda-da65-c052, GHSA-8r9f-h969-mm4m, MINI-39vr-9rhw-rv2f, MINI-5cf5-vr7m-pgf5, MINI-j6vg-pcxq-xgg3, MINI-rvcc-c6gm-5jv6, MINI-wjq4-p3rr-2vh9, PSF-2026-16, RHSA-2026:60511, ROOT-OS-DEBIAN-11-CVE-2026-3446, ROOT-OS-DEBIAN-12-CVE-2026-3446, SUSE-SU-2026:1503-1, SUSE-SU-2026:21415-1, SUSE-SU-2026:21447-1, SUSE-SU-2026:2298-1, SUSE-SU-2026:2655-1, SUSE-SU-2026:2723-1, UBUNTU-CVE-2026-3446, openSUSE-SU-2026:10579-1, openSUSE-SU-2026:10580-1 ## What is CVE-2026-3446? CVE-2026-3446 is a medium-severity vulnerability in CPython, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 data. Weakness: CWE-345 (Insufficient Verification of Data Authenticity) ## Which versions are affected by CVE-2026-3446? 3 open source packages ship an affected version, including libpython, python and python-min. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `libpython` | Bitnami | All versions | 3.13.13, 3.14.4 | | `python` | Bitnami | All versions | 3.13.13, 3.14.4 | | `python-min` | Bitnami | All versions | 3.13.13, 3.14.4 | | `python3.11` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-debug` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-devel` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-idle` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-libs` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-test` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python3.11-tkinter` | Red Hat:hummingbird:1 | All versions | 0:3.11.16-1.1.hum1 | | `python` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 2.7.18-150000.117.1 | | `python-base` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 2.7.18-150000.117.1 | | `python311` | SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | All versions | 3.11.15-150400.9.88.1 | | `python311-core` | SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | All versions | 3.11.15-150400.9.88.1 | | `python36` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 3.6.15-111.1 | | `python36-core` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 3.6.15-111.1 | | `python310` | openSUSE:Tumbleweed | All versions | 3.10.20-5.1 | | `python315` | openSUSE:Tumbleweed | All versions | 3.15.0~a8-2.1 | ## How do I fix CVE-2026-3446? Upgrade libpython to a fixed version for your release line: 3.13.13 or 3.14.4. ## Is CVE-2026-3446 being exploited? There is no known exploitation of CVE-2026-3446 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-3446 and fix it if it is affected. What it is: CVE-2026-3446 is a medium-severity vulnerability in CPython, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-3446 in the wild and no public exploit code. Affected packages and fixed versions: - libpython (Bitnami): affected all versions; fixed in 3.13.13, 3.14.4 - python (Bitnami): affected all versions; fixed in 3.13.13, 3.14.4 - python-min (Bitnami): affected all versions; fixed in 3.13.13, 3.14.4 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-3446/ (Markdown: https://insights.sbomify.com/CVE-2026-3446/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3446 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3446 - OSV: https://osv.dev/vulnerability/CVE-2026-3446 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-3446/ Summaries are generated and may contain mistakes; the official description above is the record.