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Ubuntu 26.04 LTS opam Important File Installation Issue USN-8256-1

ubuntu
Calendar Grey May 7, 2026
Dist Ubuntu Esm H88
opam in Ubuntu has a significant flaw that may allow unintended file installations leading to potential code execution risks.
opam could be made to install files in unintended locations if it installed a specially crafted package.

Summary

opam could be made to install files in unintended locations if it installed

a specially crafted package.

Software Description:

- opam: package manager for OCaml

Details:

Andrew Nesbitt discovered that opam did not properly validate file

destination paths in package install files. An attacker could use this

issue to bypass sandbox protections and write files to arbitrary locations,

possibly leading to arbitrary code execution.

Topics%20covered

Topics Covered

security advisory arbitrary code execution Ubuntu important file installation opam

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  opam                            2.5.0-1ubuntu0.1~esm1
                                  Available with Ubuntu Pro
  opam-installer                  2.5.0-1ubuntu0.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 25.10
  opam                            2.3.0-1+deb13u1build0.25.10.1
  opam-installer                  2.3.0-1+deb13u1build0.25.10.1

Ubuntu 24.04 LTS
  opam                            2.1.5-1ubuntu0.1~esm2
                                  Available with Ubuntu Pro
  opam-installer                  2.1.5-1ubuntu0.1~esm2
                                  Available with Ubuntu Pro

Ubuntu 22.04 LTS
  opam                            2.1.2-1+deb12u1build0.22.04.1
  opam-installer                  2.1.2-1+deb12u1build0.22.04.1

Ubuntu 20.04 LTS
  opam                            2.0.5-1ubuntu1+esm1
                                  Available with Ubuntu Pro
  opam-installer                  2.0.5-1ubuntu1+esm1
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-8256-1

CVE-2026-41082

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8256-1

Topics%20covered

Topics Covered

security advisory arbitrary code execution Ubuntu important file installation opam

Package Information

https://launchpad.net/ubuntu/+source/opam/2.3.0-1+deb13u1build0.25.10.1
https://launchpad.net/ubuntu/+source/opam/2.1.2-1+deb12u1build0.22.04.1

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