CVE-2026-4786

HIGHPre-NVD 7.17.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
7.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 7.1Exploit: None knownExposed services: Not assessed

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
7.1HIGHmedium confidence
EG Risk
32
EG Risk 32/100

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 (value × EchelonGraph’s weight)
Severity71% × 45%
The EG Score, 7.1 of 10.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
40th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

April 13, 2026

Last Modified

August 13, 2026

Advisory Details (8)

Auto-updated Apr 29, 2026
Patch available.
Web page

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/
Web page

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
Web page

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

https://github.com/python/cpython/issues/148169
Web page

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

https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
Web page

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

https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
Web page

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

https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
Web page

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

https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
Web page

[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 / EcosystemFix (by version range) / 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

(6 across 4 ecosystems)
Debian:14(3)
PackageVulnerable rangeFix by version rangeDependents
pypy37.3.19+dfsg-2 ... 7.3.21+dfsg-4 (9 versions)
  • every version up to 7.3.22+dfsg-1: fixed in 7.3.22+dfsg-1
—
python3.133.13.11-1 ... 3.13.9-1 (7 versions)
  • every version up to 3.13.14-1: fixed in 3.13.14-1
—
python3.143.14.0-1 ... 3.14.5~rc1-1 (22 versions)
  • every version up to 3.14.5-1: fixed in 3.14.5-1
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
python3—
  • every version up to 3.12.14-r0: fixed in 3.12.14-r0
—

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 12× in last 7d / 30× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 241 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 141 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  5. 2026-10-12 16:01 UTCEG score recompute
  6. 2026-10-11 19:44 UTCEG score recompute
  7. 2026-10-11 16:59 UTCEG score recompute
  8. 2026-10-11 14:23 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  10. 2026-10-10 20:03 UTCOSV refresh
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  20. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  22. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  23. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  24. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  25. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
Show 75 more
  1. 2026-09-21 07:49 UTCOSV refresh
  2. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  3. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  5. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  7. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  13. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  14. 2026-09-02 05:28 UTCOSV refresh
  15. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  16. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  17. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  18. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  20. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  21. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  22. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  24. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  25. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  26. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  27. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  28. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  29. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  30. 2026-08-16 06:52 UTCEG score recompute
  31. 2026-08-16 06:52 UTCVendor advisory
  32. 2026-08-16 06:52 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  33. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  34. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  35. 2026-08-14 18:16 UTCVendor advisory
  36. 2026-08-14 18:16 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  37. 2026-08-14 04:54 UTCEG score recompute
  38. 2026-08-14 04:54 UTCVendor advisory
  39. 2026-08-14 04:54 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  40. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  41. 2026-08-13 01:23 UTCEG score recompute
  42. 2026-08-13 01:23 UTCVendor advisory
  43. 2026-08-13 01:23 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  44. 2026-08-13 00:41 UTCEG score recompute
  45. 2026-08-13 00:41 UTCVendor advisory
  46. 2026-08-13 00:41 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  47. 2026-08-12 19:08 UTCEG score recompute
  48. 2026-08-12 19:08 UTCVendor advisory
  49. 2026-08-12 19:08 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  50. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  51. 2026-08-11 19:16 UTCEG score recompute
  52. 2026-08-11 19:16 UTCVendor advisory
  53. 2026-08-11 19:16 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  54. 2026-08-11 02:50 UTCEG score recompute
  55. 2026-08-11 02:50 UTCVendor advisory
  56. 2026-08-11 02:50 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  57. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  58. 2026-08-10 05:44 UTCVendor advisory
  59. 2026-08-10 05:44 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  60. 2026-08-09 17:00 UTCEG score recompute
  61. 2026-08-09 17:00 UTCVendor advisory
  62. 2026-08-09 17:00 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  63. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  64. 2026-08-09 04:17 UTCEG score recompute
  65. 2026-08-09 04:17 UTCVendor advisory
  66. 2026-08-09 04:17 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  67. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  68. 2026-08-08 02:38 UTCEG score recompute
  69. 2026-08-08 02:38 UTCVendor advisory
  70. 2026-08-08 02:38 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  71. 2026-08-07 13:55 UTCEG score recompute
  72. 2026-08-07 13:55 UTCVendor advisory
  73. 2026-08-07 13:55 UTCGHSA enrichmentGHSA-cccx-m78h-m3xw · GitHub severity HIGH · GitHub CVSS 7.1
  74. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  75. 2026-08-06 12:30 UTCVendor advisory

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4786?
CVE-2026-4786 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-4786 published?
The CVE record for CVE-2026-4786 was published on April 13, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 13, 2026; the record at its source may have been updated since.
Is CVE-2026-4786 actively exploited?
CVE-2026-4786 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-4786?
CVE-2026-4786 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-4786?
A fix for CVE-2026-4786 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-4786 are linked in the Vendor Advisories panel on this page.

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