# CVE-2026-118373: LibreSSL ocspcheck through 4.4.0 Cleartext Transmission of OCSP Requests via url2host()


- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** GHSA-56qc-c576-qq46

## What is CVE-2026-118373?

CVE-2026-118373 is a medium-severity vulnerability in OpenBSD LibreSSL, published on 28 Oct 2026. 

### Official description

LibreSSL ocspcheck through 4.4.0 contains a cleartext transmission vulnerability because url2host() discards the OCSP URL scheme and http_alloc() only selects TLS for port 443. On-path network attackers can read OCSP requests sent to https responder URLs on non-443 ports, exposing certificate serial numbers, issuer hashes, and nonces.

Weakness: CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2026-118373?


## How do I fix CVE-2026-118373?

No fix has been published for CVE-2026-118373 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-118373 being exploited?

There is no known exploitation of CVE-2026-118373 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-118373 and fix it if it is affected.

What it is: CVE-2026-118373 is a medium-severity vulnerability in OpenBSD LibreSSL, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-118373 in the wild and no public exploit code.

Affected product: OpenBSD LibreSSL. 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-2026-118373/ (Markdown: https://insights.sbomify.com/CVE-2026-118373/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-118373
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-118373
- OSV: https://osv.dev/vulnerability/CVE-2026-118373

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-118373/
Summaries are generated and may contain mistakes; the official description above is the record.