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VulnerabilityPublished Updated

CVE-2026-4786: Python2.7 · Mitgation of CVE-2026-4519 was incomplete

Affects python2.7Source GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-4786· High 7.0

Not known to be exploited · CVSS 7.0 High · fixed in 3.10.12-1~22.04.16 : patch python2.7 soon.

Data as of 9 Nov 2026, 14:22 UTC

CVSS 4.0 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 3.10.12-1~22.04.16, 3.12.3-1ubuntu0.15, 3.14.4-1ubuntu0.1
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade the Ubuntu to 3.10.12-1~22.04.16 (python3.10 package) or 3.12.3-1ubuntu0.15 (python3.12 package) or 3.14.4-1ubuntu0.1 (python3.14 package).

Affected software

ProductAffectedFixed in
Ubuntu 26.10jythonpkg:deb/ubuntu/jython?arch=source&distro=stonkingOther threatsAffected
  • =2.7.3+repack1-1build1
Fixed in–
Ubuntu 26.10pypy3pkg:deb/ubuntu/pypy3?arch=source&distro=stonkingOther threatsAffected
  • =7.3.20+dfsg-4
  • =7.3.23+dfsg-1ubuntu1
Fixed in–
Ubuntu 26.04 LTSpypy3pkg:deb/ubuntu/pypy3?arch=source&distro=resoluteOther threatsAffected
  • =7.3.20+dfsg-3
  • =7.3.20+dfsg-4
Fixed in–
Ubuntu 26.04 LTSpython3.14pkg:deb/ubuntu/python3.14?arch=source&distro=resoluteOther threatsAffected
  • <3.14.4-1ubuntu0.1
Fixed in
  • 3.14.4-1ubuntu0.1
Ubuntu 25.10jythonpkg:deb/ubuntu/jython?arch=source&distro=questingOther threatsAffected
  • =2.7.3+repack1-1
Fixed in–
Ubuntu 25.10pypy3pkg:deb/ubuntu/pypy3?arch=source&distro=questingOther threatsAffected
  • 7.3.19+dfsg-1 – 7.3.20+dfsg-3
4 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available and users should update to the patched versions of Python packages as provided by Ubuntu security notices, specifically versions 3.10.12-1~22.04.16, 3.12.3-1ubuntu0.15, and 3.14.4-1ubuntu0.1 or later. Applying these official updates will remediate the vulnerability. Standard system updates will apply the necessary patches. No additional mitigation actions are indicated by the vendor advisory.

Description

CVE-2026-4786 is a vulnerability in Python 2.7 where the mitigation for a previous flaw (CVE-2026-4519) was incomplete. Specifically, if a URL contained "%action", certain browser types could bypass the mitigation, allowing command injection via the webbrowser.open() API into the underlying shell. This vulnerability affects multiple Python 2.7 versions and some Python 3 versions prior to fixed releases. A high-severity CVSS 3.1 score of 7.1 has been assigned. Official patches are available in updated Ubuntu package versions.

References

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