CVE-2026-47221: envoyproxy envoy · NULL Pointer Dereference
Affects envoyproxy envoySource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium · fixed in 1.38.3 : update envoyproxy envoy when convenient.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.38.3, 1.37.5, 1.36.9 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 26 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.
What to do
Upgrade envoy and envoyproxy/envoy to 1.38.3, 1.37.5, 1.36.9 or 1.35.13.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| envoyproxyenvoy | Affected
| Fixed in
|
| envoyproxyenvoy | Affected
| Fixed in
|
| envoyproxyenvoy | Affected
| Fixed in
|
| envoyproxyenvoy | Affected
| Fixed in
|
GitHubenvoyproxy/envoypkg:github/envoyproxy/envoyOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Envoy versions 1.35.13, 1.36.9, 1.37.5, and 1.38.3. Users should upgrade to one of these versions or later to remediate this vulnerability. No vendor advisory was provided to indicate alternative mitigations or temporary fixes.
Description
Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.18.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the router filter contains a null pointer dereference vulnerability when handling HTTP 303 (See Other) internal redirects for body-less non-GET/HEAD requests. When a POST, PUT, DELETE, or PATCH request without a body is sent to a route configured with internal redirect policy that includes 303 in redirect_response_codes, and the upstream responds with HTTP 303, the redirect handling code attempts to drain a request body buffer that was never allocated. This results in a segmentation fault that crashes the entire Envoy process. When route configured with internal_redirect_policy including 303 in redirect_response_codes and upstream must return HTTP 303 response, an unauthenticated attacker can exploit this to cause complete denial of service, terminating all active connections. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.