Use After Free Affecting envoyproxy/envoy package, versions [1.34.0,1.34.5)[1.35.0,1.35.1)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-UNMANAGED-ENVOYPROXYENVOY-12483973
- published3 Sept 2025
- disclosed3 Sept 2025
- creditRohit Agrawal
Introduced: 3 Sep 2025
NewCVE-2025-54588 (opens in a new tab)How to fix?
Upgrade envoyproxy/envoy to version 1.34.5, 1.35.1 or higher.
Overview
Affected versions of this package are vulnerable to Use After Free while processing a pending DNS resolution. An attacker can cause abnormal process termination by triggering a completion callback for a DNS resolution that initiates new DNS resolutions or removes existing pending resolutions.
Note:
This is exploitable with the following conditions:
- Dynamic Forwarding Filter is enabled.
envoy.reloadable_features.dfp_cluster_resolves_hostsruntime flag is enabled.- The Host header is modified between the Dynamic Forwarding Filter and Router filters.
Detection:
Abnormal process termination with the Envoy::Event::DispatcherImpl::runPostCallbacks() frame in the call stack.
Workaround
This vulnerability can be mitigated by setting the envoy.reloadable_features.dfp_cluster_resolves_hosts runtime flag to false.