# CVE-2026-45047: bird-lg-go: Fatal Out-of-Memory (OOM) Denial of Service via Unbounded JSON Decoding

> An unauthenticated remote attacker can cause a fatal out-of-memory denial of service by sending an unbounded JSON payload to the API handler.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-39qr-rc93-vhqm, GO-2026-5077

## What is CVE-2026-45047?

CVE-2026-45047 is a high-severity denial of service vulnerability in xddxdd bird-lg-go, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

bird-lg-go is a BIRD looking glass in Go. Prior to 1.4.5, the apiHandler (and similarly webHandlerTelegramBot) processes user-provided JSON payloads by directly using json.NewDecoder(r.Body).Decode(&request) without restricting the maximum read size. An unauthenticated remote attacker can stream an extremely large, endless JSON payload (e.g., several Gigabytes of padding) over a single TCP connection. Because Go's JSON decoder attempts to allocate memory for the entire parsed structure, this rapidly exhausts the host's physical RAM or container limits, leading to an unrecoverable fatal error: runtime: out of memory. This vulnerability is fixed in 1.4.5.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-45047?

3 open source packages ship an affected version, including github.com/xddxdd/bird-lg-go.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/xddxdd/bird-lg-go` | Go | All versions | 0.0.0-20260507060110-0ff87024cb9e |
| `github.com/xddxdd/bird-lg-go` | Go | All versions | 0.0.0-20260507060110-0ff87024cb9e |
| `github.com/xddxdd/bird-lg-go` | Go | All versions | 0.0.0-20260507060110-0ff87024cb9e |

## How do I fix CVE-2026-45047?

Upgrade github.com/xddxdd/bird-lg-go to 0.0.0-20260507060110-0ff87024cb9e or later.

## Is CVE-2026-45047 being exploited?

There is no known exploitation of CVE-2026-45047 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45047 and fix it if it is affected.

What it is: CVE-2026-45047 is a high-severity denial of service vulnerability in xddxdd bird-lg-go, published on 27 May 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-2026-45047 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/xddxdd/bird-lg-go (Go): affected all versions; fixed in 0.0.0-20260507060110-0ff87024cb9e
- github.com/xddxdd/bird-lg-go (Go): affected all versions; fixed in 0.0.0-20260507060110-0ff87024cb9e
- github.com/xddxdd/bird-lg-go (Go): affected all versions; fixed in 0.0.0-20260507060110-0ff87024cb9e

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-2026-45047/ (Markdown: https://insights.sbomify.com/CVE-2026-45047/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45047
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45047
- OSV: https://osv.dev/vulnerability/CVE-2026-45047

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45047/
Summaries are generated and may contain mistakes; the official description above is the record.