CVE-2026-2836
Cache poisoning via insecure-by-default cache key
Description
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.
INFO
Published Date :
March 5, 2026, 12:15 a.m.
Last Modified :
March 5, 2026, 12:15 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-2836
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | a22f1246-ba21-4bb4-a601-ad51614c1513 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Upgrade Pingora to v0.8.0 or higher.
- Implement custom cache key logic.
- Include Host header in cache key.
- Include HTTP scheme in cache key.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-2836.
| URL | Resource |
|---|---|
| https://github.com/cloudflare/pingora |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-2836 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-2836
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-2836 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-2836 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Mar. 05, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added Reference https://github.com/cloudflare/pingora