CVE-2026-54783High· 7.4▾ TwilightCoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 40.7 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 9.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.1%
0.1% → 0.2%
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.
Fixed in CoreWCF v1.8.1 and v1.9.1
Ensure communication is protected by SSL/TLS to prevent capturing of signed SOAP envelope.
CoreWCF.Primitives < 1.8.1CoreWCF.Primitives >= 1.9.0, < 1.9.1Upgrade to a patched release:
CoreWCF.Primitives 1.8.1CoreWCF.Primitives 1.9.1Connected by shared product, vendor, weakness, or advisory.
CVE-2026-54774High· 7.4CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not an X.509 certificate
CVE-2026-54773Medium· 5.9CoreWCF: WS-Security signature substitution via document-wide Signature lookup
CVE-2026-54779Medium· 5.9CoreWCF: SAML token replay protection is inoperative
CVE-2026-54781High· 7.4CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced
CVE-2026-54782Critical· 10.0CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation
CVE-2026-54780Low· 3.7CoreWCF: WS-Security Reference DigestMethod Algorithm-Suite Bypass