Cloudflare: Security Vulnerabilities
A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.
Fixed in: https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff
Impact: The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.
CVSS Score
7.4
EPSS Score
0.004
Published
2025-05-22
The OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp , did not correctly validate that redirect_uri was on the allowed list of redirect URIs for the given client registration.
Fixed in: https://github.com/cloudflare/workers-oauth-provider/pull/26 https://github.com/cloudflare/workers-oauth-provider/pull/26
Impact:
Under certain circumstances (see below), if a victim had previously authorized with a server built on workers-oath-provider, and an attacker could later trick the victim into visiting a malicious web site, then attacker could potentially steal the victim's credentials to the same OAuth server and subsequently impersonate them.
In order for the attack to be possible, the OAuth server's authorized callback must be designed to auto-approve authorizations that appear to come from an OAuth client that the victim has authorized previously. The authorization flow is not implemented by workers-oauth-provider; it is up to the application built on top to decide whether to implement such automatic re-authorization. However, many applications do implement such logic.
Note: It is a basic, well-known requirement that OAuth servers should verify that the redirect URI is among the allowed list for the client, both during the authorization flow and subsequently when exchanging the authorization code for an access token. workers-oauth-provider implemented only the latter check, not the former. Unfortunately, the former is the much more important check. Readers who are familiar with OAuth may recognize that failing to check redirect URIs against the allowed list is a well-known, basic mistake, covered extensively in the RFC and elsewhere. The author of this library would like everyone to know that he was, in fact, well-aware of this requirement, thought about it a lot while designing the library, and then, somehow, forgot to actually make sure the check was in the code. That is, it's not that he didn't know what he was doing, it's that he knew what he was doing but flubbed it.
CVSS Score
6.0
EPSS Score
0.003
Published
2025-05-01
PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp . However, it was found that an attacker could cause the check to be skipped.
Fixed in:
https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27
Impact:
PKCE is a defense-in-depth mechanism against certain kinds of attacks and was an optional extension in OAuth 2.0 which became required in the OAuth 2.1 draft. (Note that the MCP specification requires OAuth 2.1.). This bug completely bypasses PKCE protection.
CVSS Score
5.3
EPSS Score
0.005
Published
2025-05-01
When copying files with rsync, octorpki uses the "-a" flag 0, which forces rsync to copy binaries with the suid bit set as root. Since the provided service definition defaults to root ( https://github.com/cloudflare/cfrpki/blob/master/package/octorpki.service ) this could allow for a vector, when combined with another vulnerability that causes octorpki to process a malicious TAL file, for a local privilege escalation.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-01-29
Improper Privilege Management vulnerability in Cloudflare WARP on Windows allows File Manipulation.
User with a low system privileges can create a set of symlinks inside the C:\ProgramData\Cloudflare\warp-diag-partials folder. After triggering the 'Reset all settings" option the WARP service will delete the files that the symlink was pointing to. Given the WARP service operates with System privileges this might lead to deleting files owned by the System user.
This issue affects WARP: before 2024.12.492.0.
CVSS Score
6.1
EPSS Score
0.003
Published
2025-01-22
Cloudflare quiche was discovered to be vulnerable to unbounded storage of information related to connection ID retirement, which could lead to excessive resource consumption. Each QUIC connection possesses a set of connection Identifiers (IDs); see RFC 9000 Section 5.1 https://datatracker.ietf.org/doc/html/rfc9000#section-5.1 . Endpoints declare the number of active connection IDs they are willing to support using the active_connection_id_limit transport parameter. The peer can create new IDs using a NEW_CONNECTION_ID frame but must stay within the active ID limit. This is done by retirement of old IDs, the endpoint sends NEW_CONNECTION_ID includes a value in the retire_prior_to field, which elicits a RETIRE_CONNECTION_ID frame as confirmation. An unauthenticated remote attacker can exploit the vulnerability by sending NEW_CONNECTION_ID frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that RETIRE_CONNECTION_ID frames can only be sent at a slower rate than they are received, leading to storage of information related to connection IDs in an unbounded queue. Quiche versions 0.19.2 and 0.20.1 are the earliest to address this problem. There is no workaround for affected versions.
CVSS Score
3.7
EPSS Score
0.007
Published
2024-03-12
Cloudflare Quiche (through version 0.19.1/0.20.0) was affected by an unlimited resource allocation vulnerability causing rapid increase of memory usage of the system running quiche server or client.
A remote attacker could take advantage of this vulnerability by repeatedly sending an unlimited number of 1-RTT CRYPTO frames after previously completing the QUIC handshake.
Exploitation was possible for the duration of the connection which could be extended by the attacker.
quiche 0.19.2 and 0.20.1 are the earliest versions containing the fix for this issue.
CVSS Score
5.9
EPSS Score
0.012
Published
2024-03-12
The Cloudflare Wordpress plugin was found to be vulnerable to improper authentication. The vulnerability enables attackers with a lower privileged account to access data from the Cloudflare API.
CVSS Score
8.1
EPSS Score
0.008
Published
2024-01-29
Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.
A local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.
Patches: The issue has been patched in commit 8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.
CVSS Score
4.0
EPSS Score
0.002
Published
2024-01-04
Sending specially crafted HTTP requests to Miniflare's server could result in arbitrary HTTP and WebSocket requests being sent from the server. If Miniflare was configured to listen on external network interfaces (as was the default in wrangler until 3.19.0), an attacker on the local network could access other local servers.
CVSS Score
7.5
EPSS Score
0.006
Published
2023-12-29