# CVE-2026-3548: Buffer overflow in CRL number parsing in wolfSSL

> Attackers can trigger heap or stack buffer overflows in wolfSSL by providing crafted CRLs, potentially leading to code execution or crashes.

- **Severity:** High 7.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Mar 2026
- **Updated:** 19 Mar 2026
- **Also known as:** DEBIAN-CVE-2026-3548, GHSA-86fv-q5vx-mw5m, JLSEC-2026-707, UBUNTU-CVE-2026-3548

## What is CVE-2026-3548?

CVE-2026-3548 is a high-severity memory corruption vulnerability in Wolfssl Wolfssl, published on 19 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-3548?

It affects 1 product.


Products: Wolfssl Wolfssl.

## How do I fix CVE-2026-3548?

Apply the vendor's patch.

## Is CVE-2026-3548 being exploited?

There is no known exploitation of CVE-2026-3548 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-2026-3548 and fix it if it is affected.

What it is: CVE-2026-3548 is a high-severity memory corruption vulnerability in Wolfssl Wolfssl, published on 19 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-3548 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-2026-3548/ (Markdown: https://insights.sbomify.com/CVE-2026-3548/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3548
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3548
- OSV: https://osv.dev/vulnerability/CVE-2026-3548

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3548/
Summaries are generated and may contain mistakes; the official description above is the record.