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CVE-2026-3446: Base64 decoding stops at first padded quad by default

Awaiting analysis
AliasesSUSE-SU-2026:1503-1SUSE-SU-2026:2655-1SUSE-SU-2026:2723-1
Published 10-04-2026Last modified 13-04-2026

Vulnerability summary

CVE-2026-3446 is a medium (CVSS 6.0) vulnerability in python software foundation cpython. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.0/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.19%
0%100%
Low · -0.04 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 21 · Related 16
MGASA-2026-0455OPENSUSE-SU-2026:10667-1OPENSUSE-SU-2026:11068-1OPENSUSE-SU-2026:11100-1OPENSUSE-SU-2026:11181-1OPENSUSE-SU-2026:21459-1

Timeline

  1. 10-04-2026
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 2 versions

EPSS trend

Probability

0.19%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

Decrease -0.04 pp

From 0.22% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu13 products
  • pypy3All versions (No fix recorded)
  • python2.7All versions (No fix recorded)
  • python3.10All versions (No fix recorded)
  • python3.11All versions (No fix recorded)
  • python3.12All versions (No fix recorded)
Redhat7 products
  • python3.11< 0:3.11.16-1.1.hum1
  • python3.11-debug< 0:3.11.16-1.1.hum1
  • python3.11-devel< 0:3.11.16-1.1.hum1
  • python3.11-idle< 0:3.11.16-1.1.hum1
  • python3.11-libs< 0:3.11.16-1.1.hum1
Suse6 products
  • python-base&distro=SUSE Linux Enterprise Module for Package Hub 15 SP7< 2.7.18-150000.117.1
  • python311-core&distro=SUSE Linux Enterprise Module for Public Cloud 15 SP4< 3.11.15-150400.9.88.1
  • python311&distro=SUSE Linux Enterprise Module for Public Cloud 15 SP4< 3.11.15-150400.9.88.1
  • python36-core&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5< 3.6.15-111.1
  • python36&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5< 3.6.15-111.1
Chainguard4 products
  • python-3.10All versions (No fix recorded)
  • python-3.11All versions (No fix recorded)
  • python-3.12All versions (No fix recorded) | < 3.12.16-r2
  • python-3.9All versions (No fix recorded)
Debian3 products
  • python3.11All versions (No fix recorded)
  • python3.13< 3.13.14-1 | < 3.13.5-2+deb13u2
  • python3.14< 3.14.4-1
Wolfi3 products
  • python-3.10All versions (No fix recorded)
  • python-3.11All versions (No fix recorded)
  • python-3.12All versions (No fix recorded) | < 3.12.16-r2
Opensuse2 products
  • python310&distro=openSUSE Tumbleweed< 3.10.20-5.1
  • python315&distro=openSUSE Tumbleweed< 3.15.0~a8-2.1
Python software foundation1 product
  • cpython< 3.13.13 | ≥ 3.14.0, < 3.14.4 | ≥ 3.15.0a1, < 3.15.0a8

8 vendors · 39 products

References

24 links
Show all 24 references