ProxySQL PROXY Protocol v1 UNKNOWN source-IP spoofing ACL bypass
CVE-2026-48772 is a critical vulnerability in ProxySQL affecting versions 2.0.0 through 3.0.8. The ProxySQL MySQL frontend incorrectly accepts a HAProxy PROXY protocol v1 header of the form PROXY UNKNOWN <addr> <addr> <port> <port>\r\n as valid input. Under the PROXY protocol v1 specification, when the transport token is UNKNOWN, any following address fields must be ignored because the proxy is declaring that the client identity is unavailable. Instead, ProxySQL parses those trailing address fields via sscanf, stores the attacker-supplied source address in the session's addr.addr field, and then uses that spoofed value in the query-rule matcher. As a result, mysql_query_rules.client_addr decisions for routing and access control can be made on attacker-controlled source IP data rather than the real peer address. This creates a remotely exploitable source-IP spoofing condition that leads to routing and ACL bypass.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
mysql_query_rules.client_addr can therefore be bypassed or manipulated. In practice, this can let untrusted clients be treated as trusted internal or administrative sources, influence read/write splitting decisions, reach routes pinned to specific application networks, bypass query-filter restrictions, and gain access to operations or backends that should be limited to particular CIDR ranges. The issue is described as a routing and ACL bypass and is remotely exploitable with no authentication or user interaction when the vulnerable frontend is reachable and configured to accept PROXY protocol headers.Mitigation
If you can’t patch tonight, do this now.
mysql-proxy_protocol_networks and avoiding the default permissive setting of '*'. Limit network reachability to the ProxySQL frontend port so only trusted proxies or load balancers can connect. Review mysql_query_rules and any ACL or routing logic that relies on client_addr, especially rules used for administrative CIDRs, schema pinning, read/write splitting, or query filtering, because those controls are unreliable on affected versions when PROXY protocol input is accepted.Remediation
Patch, then assume compromise.
UNKNOWN frames and includes regression tests. Users running ProxySQL 3.0.8 or earlier are strongly advised to upgrade.Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.