Attestation relay in CCC attested-tls-poc allows impersonation
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-346.
Summary
CCC attested-tls-poc through commit 731ca82 does not bind early attestation Evidence to the TLS connection. A remote attacker without privileges who holds an extracted attested TLS private key can forward the relying party's nonce to a genuine attester and replay the returned Evidence. This lets the attacker impersonate the attested workload and intercept data (CWE-346).
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
No affected products listed by the sources yet.
Remediation
The sources list no fixed version for attested-tls-poc.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Timeline
- 2026-10-19 Threatist record created from CVE-2026-112377
- 2026-10-20 Alias added: GHSA-hqrh-qq2r-6h96
- 2026-10-20 CISA SSVC decision points changed
- 2026-10-20 Priority changed: MEDIUM → LOW
- 2026-10-21 Priority changed: LOW → MEDIUM
References
Patch 1
Other 5
- https://github.com/CCC-Attestation/attested-tls-poc/tree/5b6c5374b3fe8b671906c8ab32f6134d9c3da26d/relay-attacks-formal
- https://github.com/ionut-arm/mbedtls/blob/f4ac7593826a506fc509c83cad73786acab1d442/library/ssl_tls13_generic.c#L430-L436
- https://datatracker.ietf.org/doc/draft-intra-handshake-fail/
- https://github.com/muhammad-usama-sardar/intra-handshake.fail
- https://github.com/CCC-Attestation/attested-tls-poc
Sources
- CVE-2026-112377 · CVE Program
- CVE-2026-112377 · NVD
- FIRST EPSS
- GHSA-hqrh-qq2r-6h96 · GitHub Advisory Database · CC BY 4.0
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