CVE-2026-3446

MEDIUMNVD 6.06.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.0 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
6.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.0Exploit: None knownExposed: 0

A fix is available — apply it.

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 v3
6.0
EG Score
6.0(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity60% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

April 10, 2026

Last Modified

April 13, 2026

Advisory Details (6)

Auto-updated Aug 3, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

Mailman 3 Title: [CVE-2026-3446] Base64 decoding stops at first padded quad by default - Security-announce - python.org

https://mail.python.org/archives/list/[email protected]/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/
github_pr

gh-145264: Do not ignore excess Base64 data after the first padded quad

Fix merged in python/cpython PR #145267 on 2026-03-22 — awaiting tagged release

https://github.com/python/cpython/pull/145267
generic

Excess Base64 data ignored after padding by default · Issue #145264 · python/cpython · GitHub

https://github.com/python/cpython/issues/145264
github_commit

commit e31c55121620 (python/cpython)

Fix landed in python/cpython commit e31c55121620 — awaiting tagged release

https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa
github_commit

commit 4561f6418a69 (python/cpython)

Fix landed in python/cpython commit 4561f6418a69 — awaiting tagged release

https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e
github_commit

commit 1f9958f909c1 (python/cpython)

Fix landed in python/cpython commit 1f9958f909c1 — awaiting tagged release

https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474

Vendor Advisories for CVE-2026-3446(5)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatpython3-12-main-3.12.13-3.1.hum12026-04-23redhat
redhatpython3-14-main-3.14.4-1.hum12026-04-11redhat
redhatpython3-13-main-3.13.13-1.hum12026-04-10redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(6 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
python2.72.7.18-10 ... 2.7.18-9 (10 versions)——
python3.93.9.10-1 ... 3.9.9-4 (29 versions)——
Debian:14(2)
PackageVulnerable rangeFixed inDependents
python3.133.13.11-1 ... 3.13.9-1 (7 versions)3.13.14-1—
python3.143.14.0-1 ... 3.14.3-5 (19 versions)3.14.4-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
python3.113.11.2-6 ... 3.11.9-1 (28 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
python3.133.13.5-2, 3.13.5-2+deb13u13.13.5-2+deb13u2—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 26× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 189 total refreshes for this CVE.

  1. 2026-09-15 03:11 UTCEPSS rescore
  2. 2026-09-13 16:47 UTCEPSS rescore
  3. 2026-09-12 15:01 UTCEPSS rescore
  4. 2026-09-11 14:53 UTCEPSS rescore
  5. 2026-09-11 09:37 UTCEPSS rescore
  6. 2026-09-10 09:34 UTCEPSS rescore
  7. 2026-09-08 22:00 UTCEPSS rescore
  8. 2026-09-07 16:01 UTCEPSS rescore
  9. 2026-09-06 13:47 UTCEPSS rescore
  10. 2026-09-04 05:06 UTCEPSS rescore
  11. 2026-09-02 14:12 UTCEPSS rescore
  12. 2026-09-02 06:14 UTCOSV refresh
  13. 2026-09-01 13:53 UTCEPSS rescore
  14. 2026-09-01 04:39 UTCEPSS rescore
  15. 2026-08-30 19:17 UTCEPSS rescore
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-28 21:41 UTCEPSS rescore
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 14:46 UTCEPSS rescore
  20. 2026-08-25 13:49 UTCEPSS rescore
  21. 2026-08-21 23:49 UTCEPSS rescore
  22. 2026-08-20 22:55 UTCEPSS rescore
  23. 2026-08-19 17:03 UTCEPSS rescore
  24. 2026-08-18 13:48 UTCEPSS rescore
  25. 2026-08-17 13:47 UTCEPSS rescore
Show 75 more
  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-16 07:00 UTCEG score recompute
  3. 2026-08-16 07:00 UTCVendor advisory
  4. 2026-08-16 07:00 UTCGHSA enrichment
  5. 2026-08-16 02:14 UTCEPSS rescore
  6. 2026-08-15 01:30 UTCEPSS rescore
  7. 2026-08-14 05:01 UTCEG score recompute
  8. 2026-08-14 05:01 UTCVendor advisory
  9. 2026-08-14 05:01 UTCGHSA enrichment
  10. 2026-08-13 22:00 UTCEPSS rescore
  11. 2026-08-12 19:14 UTCEG score recompute
  12. 2026-08-12 19:14 UTCVendor advisory
  13. 2026-08-12 19:14 UTCGHSA enrichment
  14. 2026-08-12 13:51 UTCEPSS rescore
  15. 2026-08-11 13:43 UTCEPSS rescore
  16. 2026-08-11 05:10 UTCEG score recompute
  17. 2026-08-11 05:10 UTCVendor advisory
  18. 2026-08-11 05:10 UTCGHSA enrichment
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-10 04:48 UTCEG score recompute
  21. 2026-08-10 04:48 UTCVendor advisory
  22. 2026-08-10 04:48 UTCGHSA enrichment
  23. 2026-08-09 13:46 UTCEPSS rescore
  24. 2026-08-09 04:26 UTCEG score recompute
  25. 2026-08-09 04:26 UTCVendor advisory
  26. 2026-08-09 04:26 UTCGHSA enrichment
  27. 2026-08-07 14:12 UTCEG score recompute
  28. 2026-08-07 14:12 UTCVendor advisory
  29. 2026-08-07 14:12 UTCGHSA enrichment
  30. 2026-08-06 13:46 UTCEPSS rescore
  31. 2026-08-05 23:39 UTCEG score recompute
  32. 2026-08-05 23:39 UTCVendor advisory
  33. 2026-08-05 23:39 UTCGHSA enrichment
  34. 2026-08-05 19:17 UTCEPSS rescore
  35. 2026-08-04 15:10 UTCEPSS rescore
  36. 2026-08-04 10:38 UTCEPSS rescore
  37. 2026-08-03 21:53 UTCEG score recompute
  38. 2026-08-03 21:53 UTCVendor advisory
  39. 2026-08-03 21:53 UTCGHSA enrichment
  40. 2026-08-03 10:36 UTCEPSS rescore
  41. 2026-08-02 13:40 UTCEG score recompute
  42. 2026-08-02 13:40 UTCVendor advisory
  43. 2026-08-02 13:40 UTCGHSA enrichment
  44. 2026-08-02 02:27 UTCEPSS rescore
  45. 2026-08-01 04:16 UTCEPSS rescore
  46. 2026-07-30 16:28 UTCEPSS rescore
  47. 2026-07-30 01:30 UTCEPSS rescore
  48. 2026-07-27 14:13 UTCEPSS rescore
  49. 2026-07-26 14:54 UTCEPSS rescore
  50. 2026-07-26 14:54 UTCEPSS rescore
  51. 2026-07-25 14:18 UTCEPSS rescore
  52. 2026-07-25 14:18 UTCEPSS rescore
  53. 2026-07-24 14:17 UTCEPSS rescore
  54. 2026-07-24 14:17 UTCEPSS rescore
  55. 2026-07-23 14:18 UTCEPSS rescore
  56. 2026-07-23 14:18 UTCEPSS rescore
  57. 2026-07-23 03:09 UTCEG score recompute
  58. 2026-07-22 14:08 UTCEPSS rescore
  59. 2026-07-21 15:24 UTCEPSS rescore
  60. 2026-07-20 17:08 UTCEPSS rescore
  61. 2026-07-20 13:34 UTCOSV refresh
  62. 2026-07-19 14:31 UTCEPSS rescore
  63. 2026-07-19 02:29 UTCEPSS rescore
  64. 2026-07-18 10:04 UTCEPSS rescore
  65. 2026-07-16 17:03 UTCEPSS rescore
  66. 2026-07-15 16:57 UTCEPSS rescore
  67. 2026-07-15 16:57 UTCEPSS rescore
  68. 2026-07-15 02:00 UTCEPSS rescore
  69. 2026-07-13 22:30 UTCEPSS rescore
  70. 2026-07-13 06:13 UTCEPSS rescore
  71. 2026-07-13 06:13 UTCEPSS rescore
  72. 2026-07-12 05:46 UTCEPSS rescore
  73. 2026-07-11 08:27 UTCEPSS rescore
  74. 2026-07-09 19:10 UTCEPSS rescore
  75. 2026-07-08 15:15 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-3446?
CVE-2026-3446 is a medium vulnerability published on April 10, 2026. 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…
When was CVE-2026-3446 disclosed?
CVE-2026-3446 was first published in the National Vulnerability Database on April 10, 2026, with the most recent update on April 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-3446 actively exploited?
CVE-2026-3446 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 91.4% of all scored CVEs.
What is the CVSS score of CVE-2026-3446?
CVE-2026-3446 has a CVSS v3 base score of 6.0 (NVD).
How do I remediate CVE-2026-3446?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-3446, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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