EGOR Data::DisjointSet::Shared up to 0.1 dsu.h open toctou

Summaryinfo

A vulnerability classified as problematic has been found in EGOR Data::DisjointSet::Shared up to 0.1. This vulnerability affects the function Open of the file dsu.h of the component Shared. The manipulation leads to toctou. This vulnerability is referenced as CVE-2026-65069. The attack can only be performed from a local environment. No exploit is available.

Detailsinfo

A vulnerability was found in EGOR Data::DisjointSet::Shared up to 0.1 and classified as problematic. This issue affects the function open of the file dsu.h of the component Shared. The manipulation with an unknown input leads to a toctou vulnerability. Using CWE to declare the problem leads to CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Data::DisjointSet::Shared versions before 0.02 for Perl create a world-readable mmap backing file and open it without O_EXCL or O_NOFOLLOW. The segment is created in dsu.h with open(path, O_RDWR|O_CREAT, 0666). The mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable). O_NOFOLLOW is absent, so a symlink planted at the path is followed, and O_EXCL is absent, so the open silently uses a pre-planted file instead of failing. A "Shared" segment naturally lives in a shared directory such as /tmp or /dev/shm, where any local user can read the IPC payloads stored in the world-readable segment, and a pre-planted file or symlink at the path lets a local attacker win a pre-creation race or redirect the open.

The advisory is shared at metacpan.org. The identification of this vulnerability is CVE-2026-65069 since 07/21/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

Upgrading to version 0.02 eliminates this vulnerability.

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Productinfo

Vendor

• EGOR

Name

• Data::DisjointSet::Shared

Version

• 0.1

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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