netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion

Exploitation

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

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-48043: 0.75% estimated exploitation activity in the next 30 days; percentile 55.12 (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.

Impact The DelegatingDecompressorFrameListener class orchestrates HTTP/2 decompression by embedding a per-stream EmbeddedChannel that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled ByteBuf handed to an anonymous ChannelInboundHandlerAdapter tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME.

Published by the source

11 Jun 2026, 13:28 UTC

Last modified by the source

6 Oct 2026, 19:33 UTC

Source last checked

26 Oct 2026, 16:58 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c2gf-v879-257j

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# Patch Next advisory brief: CVE-2026-48043

Advisory: netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion
IDs: CVE-2026-48043, GHSA-c2gf-v879-257j
Record: https://patchnext.com/advisories/cve-2026-48043 (revision 1, source checked 26 Oct 2026, 16:58 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.netty:netty-codec-http2 4.2.15.Final, 4.1.135.Final. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.netty:netty-codec-http2: affected <= 4.1.134.Final; >= 4.2.0.Alpha1, <= 4.2.14.Final; fixed in 4.2.15.Final, 4.1.135.Final

## Suggested inspection (read-only)
- Maven io.netty:netty-codec-http2: 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 io.netty:netty-codec-http2.
- 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-c2gf-v879-257j (GitHub-reviewed advisory GHSA-c2gf-v879-257j lists affected ranges: Maven io.netty:netty-codec-http2 >=0 =4.2.0.Alpha1 <=4.2.14.Final)

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