# CVE-2026-64613: Information disclosure in Data::Buffer::Shared

> Local attackers can read shared memory data or overwrite arbitrary files due to world-readable permissions and missing symlink protection in the Perl library.

- **Severity:** Medium 6.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Jul 2026
- **Updated:** 23 Jul 2026
- **Also known as:** GHSA-pmmg-wc48-vjhq

## What is CVE-2026-64613?

CVE-2026-64613 is a medium-severity vulnerability in EGOR Data::Buffer::Shared, published on 21 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW.

The segment is created in buf_generic.h with open(path, O_RDWR|O_CREAT|O_EXCL, 0666). O_EXCL blocks a pre-seeded file on create, but the mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable), and O_NOFOLLOW is absent, so a symlink planted at the path is followed when the segment is attached.

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 symlink at the path redirects the open to another file.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource), CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2026-64613?


## How do I fix CVE-2026-64613?

No fix has been published for CVE-2026-64613 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-64613 being exploited?

There is no known exploitation of CVE-2026-64613 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64613 and fix it if it is affected.

What it is: CVE-2026-64613 is a medium-severity vulnerability in EGOR Data::Buffer::Shared, published on 21 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64613 in the wild and no public exploit code.

Affected product: EGOR Data::Buffer::Shared. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64613/ (Markdown: https://insights.sbomify.com/CVE-2026-64613/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64613
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64613
- OSV: https://osv.dev/vulnerability/CVE-2026-64613

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64613/
Summaries are generated and may contain mistakes; the official description above is the record.