How to Fix CVE-2026-2836: https://github.com/cloudflare/pingora (Bundle Sibling)

By Sai Kiran Pandrala. Last verified: 2026-05-25.

CVE-2026-2836 is a sibling vulnerability in the same vendor advisory as CVE-2026-2833. Apply the same patched build and you close both. The technical detail below is what differs.

What's different about CVE-2026-2836?

A cache poisoning vulnerability has been found in the Pingora HTTP proxy framework’s default cache key construction. The issue occurs because the default HTTP cache key implementation generates cache keys using only the URI path, excluding critical factors such as the host header (authority). Operators relying on the default are vulnerable to cache poisoning, and cross-origin responses may be improperly served to users.

Impact

This vulnerability affects users of Pingora's alpha proxy caching feature who relied on the default CacheKey implementation. An attacker could exploit this for:

* Cross-tenant data leakage: In multi-tenant deployments, poison the cache so that users from one tenant receive cached responses from another tenant

* Cache poisoning attacks: Serve malicious content to legitimate users by poisoning shared cache entries

Cloudflare's CDN infrastructure was not affected by this vulnerability, as Cloudflare's default cache key implementation uses multiple factors to prevent cache key poisoning and never made use of the previously provided default.

Mitigation:

We strongly recommend Pingora users to upgrade to Pingora v0.8.0 or higher, which removes the insecure default cache key implementation. Users must now explicitly implement their own callback that includes appropriate factors such as Host header, origin server HTTP scheme, and other attributes their cache should vary on.

Pingora users on previous versions may also remove any of their default CacheKey usage and implement their own that should at minimum include the host header / authority and upstream peer’s HTTP scheme.

How to fix CVE-2026-2836

Apply the patched build per the primary write-up: How to Fix CVE-2026-2833. All commands, verification steps, and rollback notes for https://github.com/cloudflare/pingora are listed there.

Frequently asked questions

Does the CVE-2026-2833 patch close CVE-2026-2836?

Yes. Both CVEs are addressed by the same vendor patch. Applying the patched build closes the full bundle.

Is CVE-2026-2836 listed in CISA KEV?

No public KEV listing at the time of this writing.

Where is the official advisory?

See https://github.com/cloudflare/pingora

References

• Official vendor advisory: https://github.com/cloudflare/pingora
• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2836
• CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Primary: How to Fix CVE-2026-2833

*Written by Sai Kiran Pandrala. Part of the https://github.com/cloudflare/pingora bundle. Full procedure at how-to-fix-cve-2026-2833.*