CoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54783: 0.19% estimated exploitation activity in the next 30 days; percentile 9.07 (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.

Impact The attacker, with one captured signed SOAP envelope from a victim and no other privileges, can invoke arbitrary operations on the service as the victim principal for the lifetime of the captured signing key. There is no rate limit on replays. The DetectReplays setting on transport-security bindings does not mitigate the issue because the attack does not reuse the original timestamp — the fresh timestamp in the wsse:Security header is what the replay-detection logic inspects. Patches Fixed in CoreWCF v1.8.1 and v1.9.1 Workarounds Ensure communication is protected by SSL/TLS to prevent capturing of signed SOAP envelope.

Published by the source

19 Jun 2026, 20:47 UTC

Last modified by the source

19 Jun 2026, 20:47 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gqv6-pwcg-87r8

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# Patch Next advisory brief: CVE-2026-54783

Advisory: CoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages
IDs: CVE-2026-54783, GHSA-gqv6-pwcg-87r8
Record: https://patchnext.com/advisories/cve-2026-54783 (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: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: corewcf.primitives 1.9.1, 1.8.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet corewcf.primitives: affected < 1.8.1; >= 1.9.0, < 1.9.1; fixed in 1.8.1, 1.9.1

## Suggested inspection (read-only)
- NuGet corewcf.primitives: 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 corewcf.primitives.
- 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-gqv6-pwcg-87r8 (GitHub-reviewed advisory GHSA-gqv6-pwcg-87r8 lists affected ranges: NuGet corewcf.primitives >=0 =1.9.0 <1.9.1)

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