# CVE-2026-5507: Session Cache Restore — Arbitrary Free via Deserialized Pointer

> An attacker with session cache access can trigger an arbitrary free via deserialized pointers, potentially leading to code execution or denial of service.

- **Severity:** Medium 4.1 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 9 Apr 2026
- **Updated:** 14 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-5507, GHSA-f5fh-xmxq-55p9, JLSEC-2026-733, UBUNTU-CVE-2026-5507

## What is CVE-2026-5507?

CVE-2026-5507 is a medium-severity use after free vulnerability in Wolfssl Wolfssl, published on 9 Apr 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

When restoring a session from cache, a pointer from the serialized session data is used in a free operation without validation. An attacker who can poison the session cache could trigger an arbitrary free. Exploitation requires the ability to inject a crafted session into the cache and for the application to call specific session restore APIs.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-5507?

It affects 1 product.


Products: Wolfssl Wolfssl.

## How do I fix CVE-2026-5507?

Apply the vendor's patch.

## Is CVE-2026-5507 being exploited?

There is no known exploitation of CVE-2026-5507 in the wild and no public exploit code.

## Other vulnerabilities in Wolfssl Wolfssl

- [CVE-2024-5991](https://insights.sbomify.com/CVE-2024-5991/): Buffer overread in domain name matching (critical 10.0)
- [CVE-2021-37155](https://insights.sbomify.com/CVE-2021-37155/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-36177](https://insights.sbomify.com/CVE-2020-36177/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2896](https://insights.sbomify.com/CVE-2014-2896/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2897](https://insights.sbomify.com/CVE-2014-2897/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5507 and fix it if it is affected.

What it is: CVE-2026-5507 is a medium-severity use after free vulnerability in Wolfssl Wolfssl, published on 9 Apr 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-2026-5507 in the wild and no public exploit code.

Affected product: Wolfssl Wolfssl. 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-2026-5507/ (Markdown: https://insights.sbomify.com/CVE-2026-5507/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5507
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5507
- OSV: https://osv.dev/vulnerability/CVE-2026-5507

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5507/
Summaries are generated and may contain mistakes; the official description above is the record.