CVE-2026-4786

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-04-14. a secondary CVSS source baseline 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

A fix is available — apply it.

Mitgation of CVE-2026-4519 was incomplete. If the URL contained "%action" the mitigation could be bypassed for certain browser types the "webbrowser.open()" API could have commands injected into the underlying shell. See CVE-2026-4519 for details.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: 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
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

April 13, 2026

Last Modified

August 13, 2026

Advisory Details (8)

Auto-updated Apr 29, 2026
No patch confirmed yet.
generic

Mailman 3 [CVE-2026-4786] Incomplete mitigation of CVE-2026-4519, %action expansion for command injection to webbrowser.open() - Security-announce - python.org

https://mail.python.org/archives/list/[email protected]/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/
generic

gh-148169: Fix webbrowser `%action` substitution bypass of dash-prefix check by StanFromIreland · Pull Request #148170 · python/cpython · GitHub

https://github.com/python/cpython/pull/148170
generic

`webbrowser`: `%action` substitution can bypass the dash-prefix check · Issue #148169 · python/cpython · GitHub

https://github.com/python/cpython/issues/148169
generic

[3.11] gh-148169: Fix webbrowser `%action` substitution bypass of das… · python/cpython@f465482 · GitHub

https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
generic

[3.13] gh-148169: Fix webbrowser `%action` substitution bypass of das… · python/cpython@d6d6849 · GitHub

https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
generic

gh-148169: Fix webbrowser `%action` substitution bypass of dash-prefi… · python/cpython@d22922c · GitHub

https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
generic

[3.10] gh-148169: Fix webbrowser `%action` substitution bypass of das… · python/cpython@c5767a7 · GitHub

https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
generic

[3.14] gh-148169: Fix webbrowser `%action` substitution bypass of das… · python/cpython@28b4ad3 · GitHub

https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53

Vendor Advisories for CVE-2026-4786(20)

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

Patch Availability(30)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatpython3-0:3.6.8-21.el7_9.62026-07-06redhat
redhatrhaiis/vllm-rocm-rhel9:17823530932026-06-25redhat
redhatrhaiis/vllm-cuda-rhel9:17823528472026-06-25redhat
redhatrhaiis/model-opt-cuda-rhel9:17823529502026-06-25redhat
redhatrhaiis/vllm-spyre-rhel9:17823529192026-06-25redhat
redhatpython3.14-0:3.14.5-1.el10_22026-06-24redhat
redhatpython3.14-0:3.14.5-1.el9_82026-06-23redhat
redhatpython3.11-0:3.11.2-2.el8_8.102026-06-16redhat
redhatrhaiis/model-opt-cuda-rhel9:17806819842026-06-10redhat
redhatpython-0:2.6.6-70.el6_10.42026-06-01redhat
redhatpython3.9-0:3.9.18-3.el9_4.132026-05-28redhat
redhatrhui5/rhua-rhel9:17797982222026-05-27redhat
redhatpython3.9-0:3.9.16-1.el9_2.142026-05-20redhat
redhatpython3.9-0:3.9.10-4.el9_0.112026-05-20redhat
redhatpython3-0:3.6.8-39.el8_4.112026-05-20redhat
redhatpython3.9-0:3.9.21-2.el9_6.62026-05-20redhat
redhatpython-0:2.7.5-94.el7_9.52026-05-20redhat
redhatpython3-0:3.6.8-51.el8_8.152026-05-20redhat
redhatpython3.9-0:3.9.25-7.el9_82026-05-19redhat
redhatpython3.14-0:3.14.4-2.el10_22026-05-19redhat
redhatpython3.12-0:3.12.13-2.el9_82026-05-19redhat
redhatpython3.12-0:3.12.13-2.el10_22026-05-19redhat
redhatpython3.11-0:3.11.13-9.el9_82026-05-19redhat
redhatpython3.14-0:3.14.4-2.el9_82026-05-19redhat
redhatpython3.12-0:3.12.1-4.el9_4.132026-05-14redhat
redhatpython3-0:3.6.8-47.el8_6.132026-05-14redhat
redhatpython3.12-0:3.12.9-2.el10_0.92026-05-13redhat
redhatpython3.11-0:3.11.7-1.el9_4.132026-05-07redhat
redhatpython3.12-0:3.12.9-1.el9_6.82026-05-07redhat
redhatpython3.11-0:3.11.11-2.el9_6.72026-05-07redhat

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

(3 across 1 ecosystem)
Debian:14(3)
PackageVulnerable rangeFixed inDependents
pypy37.3.19+dfsg-2 ... 7.3.21+dfsg-4 (9 versions)7.3.22+dfsg-1—
python3.133.13.11-1 ... 3.13.9-1 (7 versions)3.13.14-1—
python3.143.14.0-1 ... 3.14.5~rc1-1 (22 versions)3.14.5-1—

Weakness Classification(2)

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

Additional Vendor Advisories

(24)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 80× 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 200 total refreshes for this CVE.

  1. 2026-08-30 19:17 UTCEPSS rescore
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-28 21:41 UTCEPSS rescore
  4. 2026-08-27 14:25 UTCEPSS rescore
  5. 2026-08-26 14:46 UTCEPSS rescore
  6. 2026-08-25 13:49 UTCEPSS rescore
  7. 2026-08-23 00:19 UTCEPSS rescore
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-20 22:55 UTCEPSS rescore
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-18 13:48 UTCEPSS rescore
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-16 06:52 UTCEG score recompute
  15. 2026-08-16 06:52 UTCVendor advisory
  16. 2026-08-16 06:52 UTCGHSA enrichment
  17. 2026-08-16 02:14 UTCEPSS rescore
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 18:16 UTCVendor advisory
  20. 2026-08-14 18:16 UTCGHSA enrichment
  21. 2026-08-14 04:54 UTCEG score recompute
  22. 2026-08-14 04:54 UTCVendor advisory
  23. 2026-08-14 04:54 UTCGHSA enrichment
  24. 2026-08-13 22:00 UTCEPSS rescore
  25. 2026-08-13 01:23 UTCEG score recompute
Show 75 more
  1. 2026-08-13 01:23 UTCVendor advisory
  2. 2026-08-13 01:23 UTCGHSA enrichment
  3. 2026-08-13 00:41 UTCEG score recompute
  4. 2026-08-13 00:41 UTCVendor advisory
  5. 2026-08-13 00:41 UTCGHSA enrichment
  6. 2026-08-12 19:08 UTCEG score recompute
  7. 2026-08-12 19:08 UTCVendor advisory
  8. 2026-08-12 19:08 UTCGHSA enrichment
  9. 2026-08-12 13:51 UTCEPSS rescore
  10. 2026-08-11 19:16 UTCEG score recompute
  11. 2026-08-11 19:16 UTCVendor advisory
  12. 2026-08-11 19:16 UTCGHSA enrichment
  13. 2026-08-11 02:50 UTCEG score recompute
  14. 2026-08-11 02:50 UTCVendor advisory
  15. 2026-08-11 02:50 UTCGHSA enrichment
  16. 2026-08-11 00:00 UTCEPSS rescore
  17. 2026-08-10 05:44 UTCVendor advisory
  18. 2026-08-10 05:44 UTCGHSA enrichment
  19. 2026-08-09 17:00 UTCEG score recompute
  20. 2026-08-09 17:00 UTCVendor advisory
  21. 2026-08-09 17:00 UTCGHSA enrichment
  22. 2026-08-09 13:46 UTCEPSS rescore
  23. 2026-08-09 04:17 UTCEG score recompute
  24. 2026-08-09 04:17 UTCVendor advisory
  25. 2026-08-09 04:17 UTCGHSA enrichment
  26. 2026-08-08 16:37 UTCEPSS rescore
  27. 2026-08-08 02:38 UTCEG score recompute
  28. 2026-08-08 02:38 UTCVendor advisory
  29. 2026-08-08 02:38 UTCGHSA enrichment
  30. 2026-08-07 13:55 UTCEG score recompute
  31. 2026-08-07 13:55 UTCVendor advisory
  32. 2026-08-07 13:55 UTCGHSA enrichment
  33. 2026-08-06 13:47 UTCEPSS rescore
  34. 2026-08-06 12:30 UTCVendor advisory
  35. 2026-08-06 12:30 UTCGHSA enrichment
  36. 2026-08-05 23:32 UTCEG score recompute
  37. 2026-08-05 23:32 UTCVendor advisory
  38. 2026-08-05 23:32 UTCGHSA enrichment
  39. 2026-08-05 19:17 UTCEPSS rescore
  40. 2026-08-05 01:19 UTCEG score recompute
  41. 2026-08-05 01:19 UTCVendor advisory
  42. 2026-08-05 01:19 UTCGHSA enrichment
  43. 2026-08-05 00:51 UTCEG score recompute
  44. 2026-08-05 00:51 UTCVendor advisory
  45. 2026-08-05 00:51 UTCGHSA enrichment
  46. 2026-08-04 15:10 UTCEPSS rescore
  47. 2026-08-04 10:39 UTCEPSS rescore
  48. 2026-08-03 21:47 UTCVendor advisory
  49. 2026-08-03 21:47 UTCGHSA enrichment
  50. 2026-08-03 02:16 UTCVendor advisory
  51. 2026-08-03 02:16 UTCGHSA enrichment
  52. 2026-08-02 13:32 UTCEG score recompute
  53. 2026-08-02 13:32 UTCVendor advisory
  54. 2026-08-02 13:32 UTCGHSA enrichment
  55. 2026-08-02 02:27 UTCEPSS rescore
  56. 2026-08-01 04:16 UTCEPSS rescore
  57. 2026-07-30 16:28 UTCEPSS rescore
  58. 2026-07-30 01:30 UTCEPSS rescore
  59. 2026-07-28 15:37 UTCEPSS rescore
  60. 2026-07-26 14:54 UTCEPSS rescore
  61. 2026-07-25 14:18 UTCEPSS rescore
  62. 2026-07-24 14:18 UTCEPSS rescore
  63. 2026-07-23 14:18 UTCEPSS rescore
  64. 2026-07-23 03:17 UTCEG score recompute▲ 0.10
  65. 2026-07-22 14:08 UTCEPSS rescore
  66. 2026-07-21 15:25 UTCEPSS rescore
  67. 2026-07-20 17:08 UTCEPSS rescore
  68. 2026-07-20 11:04 UTCOSV refresh
  69. 2026-07-19 14:31 UTCEPSS rescore
  70. 2026-07-19 14:31 UTCEPSS rescore
  71. 2026-07-19 02:29 UTCEPSS rescore
  72. 2026-07-18 10:04 UTCEPSS rescore
  73. 2026-07-16 17:03 UTCEPSS rescore
  74. 2026-07-15 16:57 UTCEPSS rescore
  75. 2026-07-15 16:57 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-4786?
CVE-2026-4786 is a high vulnerability published on April 13, 2026. Mitgation of CVE-2026-4519 was incomplete. If the URL contained "%action" the mitigation could be bypassed for certain browser types the "webbrowser.open()" API could have commands injected into the underlying shell. See CVE-2026-4519 for details.
When was CVE-2026-4786 disclosed?
CVE-2026-4786 was first published in the National Vulnerability Database on April 13, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4786 actively exploited?
CVE-2026-4786 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 78.9% of all scored CVEs.
What is the CVSS score of CVE-2026-4786?
CVE-2026-4786 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-4786?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4786, 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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