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CVE-2026-73548Disclosure(envoyproxy / envoy)

LOWCVSS 7.5 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch envoyproxy envoy systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete HTTP/1.1 request in extended CONNECT data; Envoy downgrades the request, writes the data unframed to a keep-alive HTTP/1.1 upstream, and returns the socket to the shared pool while the smuggled response remains queued. A different downstream client can then receive the attacker's response. The relevant scope boundary is that webSocket upgrades, plain CONNECT, disabled backend keep-alive, per-downstream pools, and max_requests_per_connection set to 1 are not affected by the demonstrated path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

envoyproxy CVEsBack to dashboard
0.5/ 10 priority

Sources & remediation

Patch / fix
Exploit / PoC references
Other references
Weakness type (CWE)
CWE-444

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • envoy

Threat summary

  • Patch or workaround signal is available
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 2 signals
  • Disclosure: 1 classified signal
  • Peaked 1d ago at 1 mentions (2026-09-22); latest day: 1
  • 2 total mentions across 2 days

Affected systems

Vendors
envoyproxy
Products
envoy

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-09-22: 1Mentions · 2026-10-17: 1Patch / Workaround · 2026-10-17: 1Technical Details · 2026-09-22: 1Technical Details · 2026-10-17: 109-2210-17
Signal classification2 categories
Disclosure
150.0%
Patch
150.0%
Referenced assets2 URLs
Classification over time
DateTotalLabels
2026-09-221
Disclosure1
2026-10-171
Patch1
Full discourse2 posts
  • Hugo | DevOps | Cybersecurity 🇱🇻@HugoValters
    Patch

    CVE-2026-73548 Envoy request smuggling, CVSS 7.5. Unauthenticated HTTP/2 clients can smuggle full HTTP/1.1 requests past upstream and poison the keep-alive pool. Fixed in 1.36.10, 1.37.6, 1.38.4, 1.39.1. Update now. https://www.valtersit.com/cve/CVE-2026-73548/ #CVE #infosec #Envoy #Envoyproxy #CVEALERT #CVE #infosec #Linux #XSS #valtersit #snippet #SysAdmin #cybersecurity #devsecops #devops #developer #100daysofcode #git #github #gitlab #redteam #blueteam #ethicalhacker #cybersecurityawareness #cybersecuritynews #cybersecuritytips #python #hacker #kali #ubuntu #debian #docker

    Post summary

    The tweet announces CVE-2026-73548 as an Envoy HTTP/2 request smuggling vulnerability (CVSS 7.5) and provides specific fixed versions with an explicit call to update immediately.

    0000048
    1.1K followersView on X
  • NewNormal Security@NewScanTeam
    Disclosure

    NewNormal Security turns CVEs since the previous batch into new detections, every day. 𝗗𝗮𝗶𝗹𝘆 𝗖𝗩𝗘 𝗥𝗲𝗽𝗼𝗿𝘁 — 22 Sep 2026 𝗔𝗱𝗱𝗲𝗱 to NewScan 𝘁𝗼𝗱𝗮𝘆: ✂️ Edge proxy path confusion and upgrade tunnelling — smuggle a request past the proxy's own access control (Envoy CVE-2026-73548, CVE-2026-73552, CVE-2026-73553, CVE-2026-73511, CVE-2026-73551) 🖥️ Service mesh proxy admin console reachable with no password — dump upstreams, listeners and the TLS material they reference (Envoy CVE-2026-73546) 📦 Network monitoring appliance on an unpatched build — read its stored config backups, or run commands on the box that sees every flow (ntop ntopng CVE-2026-84990, CVE-2026-82412) Test your stack with NewScan — free, self-hosted: https://newnormalsecurity.com/newscan?utm_source=x&utm_medium=social&utm_campaign=daily-cve #infosec #AppSec #RequestSmuggling #CSO #REDTEAM

    Post summary

    This daily CVE report announces new detections for several Envoy and ntopng vulnerabilities, providing brief technical descriptions of the security impacts without offering patches or exploit code.

    0000047
    6 followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appenvoyproxyenvoy---

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