VulnerabilityAwaiting Analysis
CVE-2026-4786
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.
HIGH 7.0EPSS 0.29%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.29%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 7.0 HIGHCVSS: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/M
- EPSS
- 0.29% probability · 21th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-77, CWE-88
- Source
- cna@python.org
References
- https://github.com/python/cpython/commit/28b4ad38067bbdad34edfcd03ad2de5f06387e53
- https://github.com/python/cpython/commit/a4d3edf3a6ecfde504d02126410d2a65a859b744
- https://github.com/python/cpython/commit/c5767a72838a8dda9d6dc5d3558075b055c56bca
- https://github.com/python/cpython/commit/d22922c8a7958353689dc4763dd72da2dea03fff
- https://github.com/python/cpython/commit/d6d68494be70bdbda20f89f83801ba52ec37daa4
- https://github.com/python/cpython/commit/f4654824ae0850ac87227fb270f9057477946769
- https://github.com/python/cpython/issues/148169
- https://github.com/python/cpython/pull/148170
- https://mail.python.org/archives/list/security-announce@python.org/thread/JQDUNJVB4AQNTJECSUKOBDU3XCJIPSE5/
- https://access.redhat.com/errata/RHSA-2026:10117
- https://access.redhat.com/errata/RHSA-2026:10140
- https://access.redhat.com/errata/RHSA-2026:10141
- https://access.redhat.com/errata/RHSA-2026:10711
- https://access.redhat.com/errata/RHSA-2026:10745
- https://access.redhat.com/errata/RHSA-2026:10774
- https://access.redhat.com/errata/RHSA-2026:10949
- https://access.redhat.com/errata/RHSA-2026:10950
- https://access.redhat.com/errata/RHSA-2026:11062
- https://access.redhat.com/errata/RHSA-2026:11077
- https://access.redhat.com/errata/RHSA-2026:11768
- https://access.redhat.com/errata/RHSA-2026:13692
- https://access.redhat.com/errata/RHSA-2026:13812
- https://access.redhat.com/errata/RHSA-2026:14652
- https://access.redhat.com/errata/RHSA-2026:14653
- https://access.redhat.com/errata/RHSA-2026:14656
- https://access.redhat.com/errata/RHSA-2026:16699
- https://access.redhat.com/errata/RHSA-2026:17525
- https://access.redhat.com/errata/RHSA-2026:17619
- https://access.redhat.com/errata/RHSA-2026:19019
- https://access.redhat.com/errata/RHSA-2026:19064
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.