Constrata's coordinator transit engine ciphertextContainer.UnmarshalJSON panics on attacker-controlled short ciphertexts

Exploitation

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

CVSS

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary ciphertextContainer.UnmarshalJSON decodes the third :-separated component of a vault:vX:base64... ciphertext and then unconditionally takes a 12-byte prefix slice for the AES-GCM nonce: c.nonce = fullCiphertext[:aesGCMNonceSize]. If the decoded blob is shorter than 12 bytes, the slice expression panics. The panic happens before any cryptographic operation, while the JSON body of the request is still being parsed inside the request handler. Because the handler is invoked from net/http's standard handler goroutine, the panic is recovered to a 500 response, but the request handler aborts mid-execution and the recovered panic appears in the Coordinator's logs. An authenticated workload that holds a valid mesh certificate for any WorkloadSecretID can trigger the panic at will, producing log spam, request-failure metrics, and a slow but cheap denial of service against the transit-engine endpoint. Details the panicking slice coordinator/internal/transitengineapi/crypto.go:64-88:…

Published by the source

1 Jul 2026, 18:47 UTC

Last modified by the source

1 Jul 2026, 18:47 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3ccm-4qq2-5wrp

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# Patch Next advisory brief: GHSA-3ccm-4qq2-5wrp

Advisory: Constrata's coordinator transit engine `ciphertextContainer.UnmarshalJSON` panics on attacker-controlled short ciphertexts
IDs: GHSA-3ccm-4qq2-5wrp
Record: https://patchnext.com/advisories/ghsa-3ccm-4qq2-5wrp (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/edgelesssys/contrast 1.21.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/edgelesssys/contrast: affected <= 1.20.0; fixed in 1.21.0

## Suggested inspection (read-only)
- Go github.com/edgelesssys/contrast: 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 github.com/edgelesssys/contrast.
- 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-3ccm-4qq2-5wrp (GitHub-reviewed advisory GHSA-3ccm-4qq2-5wrp lists affected ranges: Go github.com/edgelesssys/contrast >=0 <=1.20.0)

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