What is the CVSS score of CVE-2026-48497?

CVE-2026-48497 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.4%.

Which versions of Envoy are affected by CVE-2026-48497?

Envoy proxy contains a denial-of-service vulnerability that could crash service instances and impact application availability.. A patch is available.

How to fix or mitigate CVE-2026-48497?

Within 24 hours: Inventory all Envoy deployments, identify affected versions, and assess criticality to service delivery. Within 7 days: Obtain and deploy the vendor-released patch to non-production environments following vendor advisory guidance. Within 30 days: Complete production deployment of patched Envoy versions across all infrastructure.

Envoy CVE-2026-48497

EUVD-2026-39821 HIGH

Use of Incorrect Operator (CWE-480)

2026-06-26 GitHub_M

Information Disclosure Envoy Suse

7.5

CVSS 3.1 · NVD

Severity by source

Vendor (GitHub_M) PRIMARY

MEDIUM

qualitative

NVD

7.5 HIGH

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

vuln.today AI

7.5 HIGH

Unauthenticated network query crashes the process (A:H) once the UDP DNS filter is enabled; no confidentiality or integrity impact, matching the published vector.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SUSE

MEDIUM

qualitative

Primary rating from Vendor (GitHub_M).

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Updated

Jun 29, 2026 - 18:43 vuln.today

v3 (cvss_changed)

Analysis Updated

Jun 29, 2026 - 18:43 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jun 29, 2026 - 18:37 vuln.today

cvss_changed

Severity Changed

Jun 29, 2026 - 18:37 NVD

MEDIUM HIGH

CVSS changed

Jun 29, 2026 - 18:37 NVD

5.9 (MEDIUM) 7.5 (HIGH)

Patch available

Jun 26, 2026 - 19:02 EUVD

Analysis Generated

Jun 26, 2026 - 18:34 vuln.today

DescriptionNVD

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, in cases where UDP DNS filter is configured with local resolution containing a name with the length of 255 octets or remote resolution for a name of 255 octets long can complete successfully, a query with such name will result in abnormal process termination. The abnormal process termination is triggered by an invalid runtime precondition that the query name is strictly less than 255 octets, contradicting DNS specification rfc1035#section-2.3.4 that the name can be 255 or less octets. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

AnalysisAI

Remote denial of service in Envoy proxy allows attackers to crash the process by resolving a DNS name exactly 255 octets long through a configured UDP DNS filter. An off-by-one runtime precondition assumes query names are strictly less than 255 octets, contradicting RFC 1035 which permits names of up to 255 octets, so a maximally-long name that resolves successfully triggers abnormal process termination. There is no public exploit identified at time of analysis, EPSS is low (0.37%), and CISA SSVC rates exploitation as none with only partial technical impact.

Technical ContextAI

Envoy is a high-performance L3/L4 and L7 edge/service proxy widely used as the data plane in service meshes (notably Istio) and cloud-native ingress. The defect lives in Envoy's UDP DNS filter, which performs local resolution (statically configured names) or remote resolution (upstream DNS) for DNS queries. The CWE-480 (Use of Incorrect Operator) root cause is a boundary check that enforces 'name length < 255' via a runtime assertion, whereas RFC 1035 section 2.3.4 permits a domain name to be 255 octets or fewer. When a query name reaches the legal maximum of 255 octets and resolution otherwise succeeds, the invalid precondition fires and terminates the process rather than handling the valid name, converting a spec-compliant input into a crash.

RemediationAI

Vendor-released patch: upgrade to Envoy 1.35.11, 1.36.7, 1.37.3, or 1.38.1 (whichever matches your release line), as documented in advisory GHSA-j6g2-wf95-q66q (https://github.com/envoyproxy/envoy/security/advisories/GHSA-j6g2-wf95-q66q). If you cannot patch immediately, the most direct compensating control is to disable the UDP DNS filter, since the crash is only reachable through that filter - the trade-off is loss of any DNS proxying/resolution functionality that filter provides. Where the filter must remain enabled, restrict or front the UDP DNS listener so only trusted clients can submit queries and constrain which names can be resolved (avoiding successful resolution of 255-octet names), accepting that this narrows legitimate resolution and adds operational complexity. For service-mesh users (e.g., Istio), update to a mesh release that bundles a fixed Envoy build.