knative.dev/pkg admission webhooks allow unbounded request-body memory exhaustion

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54462: 0.38% estimated exploitation activity in the next 30 days; percentile 31.62 (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.

⚠️ Update (verification, 2026-05-19): C-2 confirmed end-to-end — 4.5× amplification observed (worse than the advisory's conservative 2× claim) Built a Go PoC (`cmd/poc-c2/main.go`) that runs the exact 8-line vulnerable snippet from `webhook/admission.go:109-117` verbatim under the same `http.HandlerFunc` shape (the full production `admissionHandler` at `:85` requires `*Webhook` + `AdmissionController` + an informer-synced channel + controller-runtime / client-go scaffolding — the bug is the missing `http.MaxBytesReader`, nothing else in the handler). Bound to `127.0.0.1:18098`. PoC client streamed 2 GiB of `a` bytes over a raw TCP socket. `runtime.MemStats.HeapAlloc` sampler: ``` baseline: HeapAlloc = 0.32 MiB peak: HeapAlloc = 9 217.38 MiB = 9.00 GiB ratio: 4.50× the…

Published by the source

28 Oct 2026, 21:20 UTC

Last modified by the source

28 Oct 2026, 21:30 UTC

Source last checked

29 Oct 2026, 06:45 UTC

1. Revision 2 · amended · 29 Oct 2026

   Amended from osv record GHSA-2hw4-c9m4-f2fj

2. Revision 1 · created · 28 Oct 2026

   Published from ghsa record GHSA-2hw4-c9m4-f2fj

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# Patch Next advisory brief: CVE-2026-54462

Advisory: knative.dev/pkg admission webhooks allow unbounded request-body memory exhaustion
IDs: CVE-2026-54462, GHSA-2hw4-c9m4-f2fj
Record: https://patchnext.com/advisories/ghsa-2hw4-c9m4-f2fj (revision 2, source checked 29 Oct 2026, 06:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: knative.dev/pkg 0.0.0-20260531000007-52dbd5ece63f. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go knative.dev/pkg: affected < 0.0.0-20260531000007-52dbd5ece63f; fixed in 0.0.0-20260531000007-52dbd5ece63f

## Suggested inspection (read-only)
- Go knative.dev/pkg: 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 knative.dev/pkg.
- 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-2hw4-c9m4-f2fj (GitHub-reviewed advisory GHSA-2hw4-c9m4-f2fj lists affected ranges: Go knative.dev/pkg >=0 <0.0.0-20260531000007-52dbd5ece63f)
- Verified: https://osv.dev/vulnerability/GHSA-2hw4-c9m4-f2fj (OSV record GHSA-2hw4-c9m4-f2fj lists affected ranges: Go knative.dev/pkg >=0 <0.0.0-20260531000007-52dbd5ece63f (fixed))

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