CVE-2026-4786
Incomplete mitigation of CVE-2026-4519, %action expansion for command injection to webbrowser.open()
At a glance
- Severity
- HIGH 7.0
- EPSS
- EPSS 0.29 % · percentile 21 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- PSF
- NVD status
- Awaiting Analysis
Description
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 7.0 | CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N | PSF |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L | redhat-SADP |
| CVSS 4.0 | HIGH 7.0 | CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cna@python.org (Secondary) |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2026-22134
- GCVE · GCVE-0-2026-4786
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0958 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0667 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0556 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0430 — Multiples vulnérabilités dans Python · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Python Software Foundation · CPython | affected 0 < 3.10.21 ; affected 3.11.0 < 3.11.16 ; affected 3.12.0 < 3.12.14 ; affected 3.13.0 < 3.13.14 ; affected 3.14.0a1 < 3.14.5rc1 ; affected 3.15.0a1 < 3.15.0b1 |
References
- https://github.com/python/cpython/pull/148170
- https://github.com/python/cpython/issues/148169
- https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/
- https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
- https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
- https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
- https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53
- https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
- https://github.com/python/cpython/commit/a4d3edf3a6ecfde504d02126410d2a65a859b744
- https://access.redhat.com/security/cve/CVE-2026-4786
- https://bugzilla.redhat.com/show_bug.cgi?id=2458049
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4786.json
- https://access.redhat.com/errata/RHSA-2026:22144
- https://access.redhat.com/errata/RHSA-2026:19589
- https://access.redhat.com/errata/RHSA-2026:35838
- https://access.redhat.com/errata/RHSA-2026:13812
- https://access.redhat.com/errata/RHSA-2026:16699
- https://access.redhat.com/errata/RHSA-2026:10711
- https://access.redhat.com/errata/RHSA-2026:19064
- https://access.redhat.com/errata/RHSA-2026:19019
- https://access.redhat.com/errata/RHSA-2026:28581
- https://access.redhat.com/errata/RHSA-2026:11077
- https://access.redhat.com/errata/RHSA-2026:11062
- https://access.redhat.com/errata/RHSA-2026:10950
- https://access.redhat.com/errata/RHSA-2026:19590
- https://access.redhat.com/errata/RHSA-2026:17619
- https://access.redhat.com/errata/RHSA-2026:19549
- https://access.redhat.com/errata/RHSA-2026:26187
- https://access.redhat.com/errata/RHSA-2026:19571
- https://access.redhat.com/errata/RHSA-2026:19570
- https://access.redhat.com/errata/RHSA-2026:13692
- https://access.redhat.com/errata/RHSA-2026:21682
- https://access.redhat.com/errata/RHSA-2026:14653
- https://access.redhat.com/errata/RHSA-2026:17525
- https://access.redhat.com/errata/RHSA-2026:19576
- https://access.redhat.com/errata/RHSA-2026:14652
- https://access.redhat.com/errata/RHSA-2026:14656
- https://access.redhat.com/errata/RHSA-2026:10949
- https://access.redhat.com/errata/RHSA-2026:10774
- https://access.redhat.com/errata/RHSA-2026:10745
- https://access.redhat.com/errata/RHSA-2026:19216
- https://access.redhat.com/errata/RHSA-2026:19175
- https://access.redhat.com/errata/RHSA-2026:19177
- https://access.redhat.com/errata/RHSA-2026:19176
- https://access.redhat.com/errata/RHSA-2026:28247
- https://access.redhat.com/errata/RHSA-2026:25096
- https://access.redhat.com/errata/RHSA-2026:30078
- https://access.redhat.com/errata/RHSA-2026:30089
- https://access.redhat.com/errata/RHSA-2026:30088
- https://access.redhat.com/errata/RHSA-2026:30087
- +8 more
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |