CVE-2026-56285: Nitter - Server-Side Request Forgery in /video Media Proxy Endpoint

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-29 · updated 2026-10-25
Weakness: CWE-918

Description

Nitter's /video media proxy endpoint fails to validate target URLs against Twitter/X domains and uses a hardcoded default HMAC key, allowing unauthenticated attackers to compute valid HMACs for arbitrary URLs. Attackers can retrieve HTTP responses from any host reachable by the server, including cloud metadata services and internal network resources.

References

https://github.com/zedeus/nitter/commit/44b2f096f67da2cc257a0e262a94a7ae79e95d47
https://github.com/zedeus/nitter/issues/1411
https://www.vulncheck.com/advisories/nitter-server-side-request-forgery-in-video-media-proxy-endpoint
https://github.com/zedeus/nitter/issues/1411

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