TShock allows chat while not fully connected, possible ban evasion

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

This issue was reported to TShock by @ohayo, but was found by the Discord user by the name of sofurry.com. Please note that this user does not own this domain on the internet, just the discord handle. TShock overrides certain Terraria vanilla systems, including chat, and the connection handling, for its own purposes, like enforcing bans. When clients connect but do not complete the connection handshake (e.g., send message number 6), they can "exist" on the server, occupy a player slot, chat, and receive data from the server despite not being fully connected. Individuals who exploit this will be able to effectively harass the server, observe the server, and utilize server resources even if banned from the server. For servers that operate with a proxy that strictly enforces the connection handshake/sequence, this is not an issue, but for smaller servers or servers running vanilla TShock this is an issue worth patching for. PR body supplied by @ohayo (patch writer): Terraria's standard…

Published by the source

3 Feb 2025, 16:02 UTC

Last modified by the source

3 Feb 2025, 16:02 UTC

Source last checked

26 Oct 2026, 17:03 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-f8mx-cwfh-7hr2

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# Patch Next advisory brief: GHSA-f8mx-cwfh-7hr2

Advisory: TShock allows chat while not fully connected, possible ban evasion
IDs: GHSA-f8mx-cwfh-7hr2
Record: https://patchnext.com/advisories/ghsa-f8mx-cwfh-7hr2 (revision 1, source checked 26 Oct 2026, 17:03 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: tshock 5.2.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet tshock: affected <= 5.2.1; fixed in 5.2.2

## Suggested inspection (read-only)
- NuGet tshock: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on tshock.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-f8mx-cwfh-7hr2 (GitHub-reviewed advisory GHSA-f8mx-cwfh-7hr2 lists affected ranges: NuGet tshock >=0 <=5.2.1)

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