# idunno.Bluesky, idunno.AtProto and idunno.AtProto.OAuthCallback Denial of Service Vulnerability

Advisory record · `GHSA-8fh9-c4jq-94h4`

- **Identifiers:** `GHSA-8fh9-c4jq-94h4`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-129](https://cwe.mitre.org/data/definitions/129.html)
- **Tags:** [CWE-129](https://agentprime.io/advisories/tag/cwe-129.md)
- **Published:** 13 Mar 2026
- **Updated:** 13 Mar 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 13 Mar 2026, 20:50 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `idunno.AtProto` (NuGet): affected `<1.7.0`; fixed in `1.7.0`
- `idunno.AtProto.OAuthCallback` (NuGet): affected `<1.7.0`; fixed in `1.7.0`
- `idunno.Bluesky` (NuGet): affected `<1.7.0`; fixed in `1.7.0`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 31 Oct 2026, 15:22 UTC: First seen by agentprime
- 31 Oct 2026, 15:22 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-8fh9-c4jq-94h4)

## Sources

- [GitHub Advisory Database: GHSA-8fh9-c4jq-94h4](https://github.com/advisories/GHSA-8fh9-c4jq-94h4)
- [OSV: GHSA-8fh9-c4jq-94h4](https://osv.dev/vulnerability/GHSA-8fh9-c4jq-94h4)
- <https://github.com/blowdart/idunno.Bluesky/security/advisories/GHSA-8fh9-c4jq-94h4>
- <https://github.com/dotnet/announcements/issues/384>
- <https://github.com/blowdart/idunno.Bluesky>
- <https://www.cve.org/CVERecord?id=CVE-2026-26127>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-8fh9-c4jq-94h4>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-8fh9-c4jq-94h4/>. Everything for agents: <https://agentprime.io/llms.txt>.