CVE-2026-73552

LOWCVSS 7.5 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

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 HTTP RBAC accepts RFC-valid opaque header bytes but evaluates safe_regex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

0.0/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-20

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

NONE

Threat summary

  • 1 mentions across 1 observed day

What's happening

  • 1 total mentions across 1 day

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-09-22: 109-22
Referenced assets1 URL
Full discourse1 post
  • NewNormal Security@NewScanTeam

    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

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