Envoy vulnerable to crash for scoped ip address during DNS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-26310: 0.41% estimated exploitation activity in the next 30 days; percentile 35.52 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Calling Utility::getAddressWithPort with a scoped IPv6 addresses causes a crash. This utility is called in the data plane from the originalsrc filter and the dns filter. Details The crashing function is Utility::getAddressWithPort. The crash occurs if a string containing a scoped IPv6 address is passed to this function. This vulnerability affects: 1. The original src filter: If the filter is configured and the original source is a scoped IPv6 address, it will cause a crash. 2. DNS response address resolution: If a DNS response contains a scoped IPv6 address, this will also trigger the crash. PoC To reproduce the vulnerability: 1. Method A (Original Src Filter): Configure the original src filter in Envoy and provide a scoped IPv6 address as the original source. 2. Method B (DNS Resolution): Trigger a DNS resolution process within Envoy where the DNS response contains a scoped IPv6 address. Impact This is a Denial of Service (DoS) vulnerability. It impacts users who have the…

Published by the source

10 Mar 2026, 18:16 UTC

Last modified by the source

11 Mar 2026, 20:42 UTC

Source last checked

26 Oct 2026, 15:15 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3cw6-2j68-868p

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# Patch Next advisory brief: CVE-2026-26310

Advisory: Envoy vulnerable to crash for scoped ip address during DNS
IDs: CVE-2026-26310, GHSA-3cw6-2j68-868p
Record: https://patchnext.com/advisories/cve-2026-26310 (revision 1, source checked 26 Oct 2026, 15:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/envoyproxy/envoy: affected >= 1.37.0, <= 1.37.0; >= 1.36.0, <= 1.36.4; >= 1.35.0, <= 1.35.8; <= 1.34.12

## Suggested inspection (read-only)
- Go github.com/envoyproxy/envoy: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/envoyproxy/envoy.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3cw6-2j68-868p (GitHub-reviewed advisory GHSA-3cw6-2j68-868p lists affected ranges: Go github.com/envoyproxy/envoy >=1.37.0 =1.36.0 =1.35.0 =0 <=1.34.12)

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