OpAMP client reads unbounded HTTP response bodies

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-2026-42348: 0.31% estimated exploitation activity in the next 30 days; percentile 24.07 (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 When receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. Details #2926 introduced the initial HTTP transport components which uses ReadAsByteArrayAsync to copy the HttpResponseMessage.Content into a byte array. This code path allows an unbounded read of the entire HTTP response message. Impact If an application using the OpAMP client is configured to use an OpAMP server that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response, the application could have its memory exhausted and create a denial-of-service condition. Mitigation The application's…

Published by the source

5 May 2026, 21:57 UTC

Last modified by the source

13 May 2026, 16:27 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-w2jh-77fq-7gp8

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# Patch Next advisory brief: CVE-2026-42348

Advisory: OpAMP client reads unbounded HTTP response bodies
IDs: CVE-2026-42348, GHSA-w2jh-77fq-7gp8
Record: https://patchnext.com/advisories/cve-2026-42348 (revision 1, source checked 26 Oct 2026, 17:04 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 fix available; fixed versions by package: opentelemetry.opamp.client 0.2.0-alpha.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet opentelemetry.opamp.client: affected < 0.2.0-alpha.1; fixed in 0.2.0-alpha.1

## Suggested inspection (read-only)
- NuGet opentelemetry.opamp.client: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on opentelemetry.opamp.client.
- 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-w2jh-77fq-7gp8 (GitHub-reviewed advisory GHSA-w2jh-77fq-7gp8 lists affected ranges: NuGet opentelemetry.opamp.client >=0 <0.2.0-alpha.1)

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