CVE-2026-112377

critical

Description

CCC Attestation SIG attested-tls-poc through commit 731ca82 fails to bind early attestation Evidence to the TLS connection, allowing attackers to relay valid Evidence from a genuine attester. Attackers holding an extracted attested TLS private key can forward the relying party's nonce to a genuine attester and replay its Evidence to impersonate the attested workload and intercept data.

References

https://www.vulncheck.com/advisories/ccc-attestation-sig-attested-tls-poc-through-commit-731ca82-attestation-relay-attack

https://github.com/muhammad-usama-sardar/intra-handshake.fail

https://github.com/ionut-arm/mbedtls/blob/f4ac7593826a506fc509c83cad73786acab1d442/library/ssl_tls13_generic.c#L430-L436

https://github.com/CCC-Attestation/attested-tls-poc/tree/5b6c5374b3fe8b671906c8ab32f6134d9c3da26d/relay-attacks-formal

https://github.com/CCC-Attestation/attested-tls-poc/pull/58

https://github.com/CCC-Attestation/attested-tls-poc

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-104535

https://datatracker.ietf.org/doc/draft-intra-handshake-fail/

Details

Source: Mitre, NVD

Published: 2026-10-19

Updated: 2026-10-20

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 7.4

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

Severity: High

CVSS v4

Base Score: 9.1

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00178