# CVE-2026-100349: kin-openapi openapi3filter: nil-pointer panic in ValidateResponse on a response header declared with content

> A nil-pointer dereference in kin-openapi causes a panic during response validation, leading to denial of service for applications processing untrusted OpenAPI specifications.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-100349, ECHO-94bc-babb-e070, GHSA-74vm-87hj-r66f, MINI-2c59-c62r-f5m2, MINI-3pcc-373v-xf5g, MINI-4q9c-fqc2-69cc, MINI-5pf7-qcq5-4w4r, MINI-5r85-xrgm-rw2f, MINI-6m84-qf54-366j, MINI-7f33-rqhq-wp65, MINI-8r3r-fwrc-hjwj, MINI-c23x-v467-mm3m, MINI-cgqq-58wq-28g8, MINI-f7w3-7qrj-cwm2, MINI-ghp3-j3vh-74xf, MINI-h36c-qjf2-6mcg, MINI-j635-xxq6-8qqr, MINI-j6m6-cpqg-q2pv, MINI-jf6w-rww5-97j4, MINI-jfmc-w4c6-qmff, MINI-jrh8-c525-c8g9, MINI-m8f8-mfj7-6vhf, MINI-p8g5-654g-27fh, MINI-q374-5j3c-2x84, MINI-rvgg-m8qv-h9hp, MINI-v3q8-6c6w-6hjv, MINI-v624-gcpw-r9xf, MINI-vmfq-h4gp-phwg, MINI-vmvw-c99c-w636, MINI-wc6g-rgjc-jjmm, MINI-wpjq-f74v-g26j, MINI-x3c2-v27q-ppvx, MINI-x48g-6p8g-mq7v, MINI-xfx5-xf84-4rpr, MINI-xp75-crrg-48fm, UBUNTU-CVE-2026-100349

## What is CVE-2026-100349?

CVE-2026-100349 is a high-severity vulnerability in getkin kin-openapi, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

kin-openapi is a Go project for handling OpenAPI files. Prior to 0.146.0, openapi3filter.ValidateResponse passes a nil response header schema to decodeValue when an OpenAPI document declares the header with content instead of schema. The document passes validation, but every response validation for the affected operation dereferences the nil schema and panics even when the response does not contain the declared header. Applications that ingest an untrusted specification can expose this as remote availability impact, while applications using only trusted local specifications still crash when the affected operation is exercised. This issue is fixed in version 0.146.0.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-100349?

2 open source packages ship an affected version, including github.com/getkin/kin-openapi.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/getkin/kin-openapi` | Go | All versions | 0.146.0 |
| `github.com/getkin/kin-openapi` | Go | All versions | 0.146.0 |

## How do I fix CVE-2026-100349?

Upgrade github.com/getkin/kin-openapi to 0.146.0 or later.

## Is CVE-2026-100349 being exploited?

There is no known exploitation of CVE-2026-100349 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100349 and fix it if it is affected.

What it is: CVE-2026-100349 is a high-severity vulnerability in getkin kin-openapi, published on 15 Oct 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-2026-100349 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/getkin/kin-openapi (Go): affected all versions; fixed in 0.146.0
- github.com/getkin/kin-openapi (Go): affected all versions; fixed in 0.146.0

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-2026-100349/ (Markdown: https://insights.sbomify.com/CVE-2026-100349/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100349
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100349
- OSV: https://osv.dev/vulnerability/CVE-2026-100349

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100349/
Summaries are generated and may contain mistakes; the official description above is the record.