Threat landscape
high

Microsoft GitHub Enterprise: Schwachstelle ermöglicht Manipulation von Dateien

WID-SEC-2026-2667 · first 06.08.2026 · updated 06.08.2026 · CVSS 9,1

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What it is about

GitHub ist ein netzbasierter Dienst zur Versionsverwaltung für Software-Entwicklungsprojekte. Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Microsoft GitHub Enterprise ausnutzen, um Dateien zu manipulieren.

Under what conditions?

Over the network and without logging in. This is the most dangerous combination: attackers can scan reachable devices automatically.

What can happen in the worst case

An attacker could use the vulnerability to

  • Dateien zu manipulieren

Am I affected?

Affected according to the BSI:

  • Microsoft GitHub Enterprise Server <3.21.4
  • Microsoft GitHub Enterprise Server <3.20.6
  • Microsoft GitHub Enterprise Server <3.19.10
  • Microsoft GitHub Enterprise Server <3.18.13
  • Microsoft GitHub Enterprise Server <3.17.19

The installed version is usually shown under “Help → About” or in the device’s admin interface.

What helps?

Update to at least:

  • Microsoft GitHub Enterprise Server 3.21.4
  • Microsoft GitHub Enterprise Server 3.20.6
  • Microsoft GitHub Enterprise Server 3.19.10
  • Microsoft GitHub Enterprise Server 3.18.13
  • Microsoft GitHub Enterprise Server 3.17.19

Is the vulnerability already being exploited?

None of the CVEs is in the CISA catalogue of exploited vulnerabilities. That does not mean there are no attacks, only that none are documented.

Information and sources

CVE: CVE-2026-17556

Source: BSI warning and information service (CERT-Bund); CISA. The assessment of the conditions is my reading of the BSI text; the external pages are in their original language.

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