CVE-2026-77987: A server-side request forgery (SSRF) vulnerability was identified in the notebook viewer of GitHub Enterprise Server. The notebook viewer validated the scheme and host of a user-supplied URL but did not validate the port
What it means
NIST National Vulnerability Database ha pubblicato CVE-2026-77987. La rilevanza va confermata rispetto alle tecnologie effettivamente in uso.
Why it matters
Il segnale diventa operativo solo se prodotto, versione o servizio sono presenti nel perimetro.
Recommended actions
- Confermare l'applicabilita consultando la fonte ufficiale e l'inventario asset.
- Pianificare mitigazione o aggiornamento secondo criticita e rischio di interruzione.
Translation in progress
The official content is available in the original language. The Italian version will be published once automated checks are complete.
Text acquired from the source
A server-side request forgery (SSRF) vulnerability was identified in the notebook viewer of GitHub Enterprise Server. The notebook viewer validated the scheme and host of a user-supplied URL but did not validate the port, allowing requests to be directed to internal services listening on other ports of the same appliance. Response bodies were not returned to the requester, but response timing acted as an oracle that allowed instance secrets to be extracted character by character. An extracted secret could then be used in a separate interaction with an internal service to obtain remote code execution on the appliance. Exploitation required network access to the instance and was unauthenticated when private mode was disabled, or required any authenticated user when private mode was enabled. This vulnerability affected GitHub Enterprise Server versions 3.17 through 3.22 and was fixed in versions 3.22.1, 3.21.6, 3.20.8, 3.19.12, 3.18.15, and 3.17.21. This vulnerability was reported through the GitHub Bug Bounty program.
- Source
- NIST National Vulnerability Database
- Publishing entity
- NIST National Vulnerability Database
- Entity type
- National authority
- Area
- North America · US
- Original language
- en · translation in preparation
- Publication
- 22/09/2026 23:17
- CVE
- CVE-2026-77987
- Classification
- Critical
- Stated country
- US
Affected products and versions
The official sources queried do not yet expose a list of affected versions. No automatic inference is made.