# CVE-2026-110598: Libyal libpff through 20260926 heap out-of-bounds read via libpff_record_entry_get_multi_value

> Attackers can cause crashes and leak heap memory by crafting malicious PST/OST files with invalid multi-value offsets in libpff.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-110598, GHSA-9f2v-576g-7mp5, UBUNTU-CVE-2026-110598

## What is CVE-2026-110598?

CVE-2026-110598 is a medium-severity vulnerability in libyal libpff, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Libyal libpff through 20260926 contains an integer underflow in libpff_record_entry_get_multi_value() that allows attackers to trigger heap out-of-bounds reads via non-monotonic multi-value offsets. Attackers can craft PST, OST or PAB files with decreasing PT_MV_STRING8, PT_MV_UNICODE or PT_MV_BINARY offsets to crash libpff, pypff or pffexport and expose adjacent heap memory.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-110598?


## How do I fix CVE-2026-110598?

No fix has been published for CVE-2026-110598 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-110598 being exploited?

There is no known exploitation of CVE-2026-110598 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110598 and fix it if it is affected.

What it is: CVE-2026-110598 is a medium-severity vulnerability in libyal libpff, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-110598 in the wild and no public exploit code.

Affected product: libyal libpff. 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-2026-110598/ (Markdown: https://insights.sbomify.com/CVE-2026-110598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110598
- OSV: https://osv.dev/vulnerability/CVE-2026-110598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110598/
Summaries are generated and may contain mistakes; the official description above is the record.