---
title: "Security digest: September 18, 2023"
url: https://erroneo.us/security/2023-09-18/
description: "September 18, 2023 vulnerability digest: 1 brief (TeamCity CVE-2023-42793: Auth Bypass to RCE…). What to patch and who can relax."
type: security-digest-day
section: "Security Digest"
date_published: 2023-09-18
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
license: All rights reserved. Quote with attribution and a link.
---

# Security digest: September 18, 2023

1 editorial brief.

## Take stock

- Check exposure: TeamCity CVE-2023-42793: Auth Bypass to RCE, State-Exploited . Owners of self-hosted TeamCity servers that ran a version before 2023.05.4 while reachable from the internet, and anyone still running an old build protected only by the patch plugin.
- None of it touches your stack? Then there is nothing to do today. That is a result, not a failure to read carefully.

## Editorial briefs

- **Check exposure** [TeamCity CVE-2023-42793: Auth Bypass to RCE, State-Exploited](https://erroneo.us/security/briefs/teamcity-cve-2023-42793-auth-bypass-rce/index.md): Fixed since September 2023 and mass-exploited since; confirm no TeamCity server is still on an old build, and if one was internet-facing and unpatched in late 2023, hunt for a planted foothold rather than assuming the later upgrade cleaned it.

## Known exploited (CISA KEV)

None.

## Critical advisories

None.

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Source page: https://erroneo.us/security/2023-09-18/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt