dbcve.org
EnvoyApplication · Envoyproxy

CVE-2026-48743

HIGH · 7.5 CVSS v3.1 Published 2026-06-26
Fix available
A fix is available. Upgrade to 1.35.13 / 1.36.9 or later.
See remediation →
84/100
Remediation priority · High
Public exploit Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer (HEADERS with FIN / headers-only close) but still carries a nonzero Content-Length into a complete upstream HTTP/1 request with unresolved body debt. In an HTTP/1 upstream deployment where the origin replies before reading the declared body and keeps the connection reusable, the beginning of the next Envoy-generated upstream request can be consumed as the first request's body. The remaining bytes are then parsed by the origin as a new HTTP/1 request. This was reproduced as a route-bypass/desync: direct /pwn was denied by Envoy, but the second downstream H3 stream received the response for backend-parsed GET /pwn HTTP/1.1. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
EnvoyApplication
Affected:>= 1.35.0, < 1.35.13>= 1.36.0, < 1.36.9>= 1.37.0, < 1.37.5>= 1.38.0, < 1.38.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.35.13 / 1.36.9 / 1.37.5 or later
Fixed in 1.35.131.36.91.37.5
Recommended fix High confidence

Upgrade to Envoy 1.38.1 (or latest 1.38.x), or the appropriate fixed version for your branch: 1.35.11, 1.36.7, or 1.37.3

  1. 1. Identify your current Envoy version using `envoy --version` or checking your deployment configuration
  2. 2. Determine which version branch you are running (1.35.x, 1.36.x, 1.37.x, or 1.38.x)
  3. 3. Plan the upgrade to the corresponding fixed version for your branch
  4. 4. For Envoy 1.35.x: upgrade to 1.35.11 or later
  5. 5. For Envoy 1.36.x: upgrade to 1.36.7 or later
  6. 6. For Envoy 1.37.x: upgrade to 1.37.3 or later
  7. 7. For Envoy 1.38.x: upgrade to 1.38.1 or later
  8. 8. After upgrade, verify the fix by testing HTTP/3 to HTTP/1 transcoding with Content-Length headers
Caveat Review Envoy release notes for your target version; major version upgrades (e.g., 1.35 to 1.38) may introduce breaking changes in configuration deprecations or API changes

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-48743 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-48743 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data