Use After Free in Envoyproxy Envoy
CVE-2026-48090
Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.37.0 until 1.37.5 and 1.38.3, the HTTP OAuth2 filter (envoy.filters.http.oauth2) can leave an in-flight async token exchange attached to a downstream stream that has already been torn down. A late AsyncClient completion can still invoke OAuth2Filter methods that use StreamDecoderFilterCallbacks after that object’s lifetime has ended, causing undefined behavior, worker crashes (availability loss), and use-after-free / invalid-vptr failures under AddressSanitizer. This is a memory-safety / lifetime issue in the data plane, not a trivial config bug. Remote code execution is not claimed here; the primary demonstrated impact is DoS via crash and UB; any further impact would be deployment- and allocator-dependent. This vulnerability is fixed in 1.37.5 and 1.38.3.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (45.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Envoyproxy Envoy — versions >= 1.38.0, < 1.38.3, >= 1.37.0, < 1.37.5
Weakness classification (CWE)
References
- github.com/envoyproxy/envoy/security/advisories/GHSA-3cj2-c63f-q26f (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-48090?
- CVE-2026-48090 is a medium-severity vulnerability in Envoyproxy Envoy, classified under Use After Free. CVSS score: 5.9/10. Published 2026-06-26.
- How severe is CVE-2026-48090?
- Medium severity. CVSS v3 base score is 5.9 out of 10.