CVE-2026-61810

libspdm: SPDM (DSP0274) FINISH transcript under-specifies the new 1.4 OpaqueData fields

Published Nov 11, 2026 CVSS 4.0 · 6 Medium EPSS < 1% KEV · Not listed
Description
libspdm is a sample implementation that follows the DMTF SPDM specifications. In version 1.4.0, both the FINISH request (Table 80) and the FINISH_RSP response (Table 81) gained two new fields, OpaqueDataLength and OpaqueData, placed before the trailing signed/authenticated field. The transcript definitions used to compute and verify the FINISH signature, the FINISH HMAC (RequesterVerifyData), and the FINISH_RSP HMAC (ResponderVerifyData) were not updated and still terminate with a step of the form. Per DSP0274, the "SPDM Header Fields" are only the four header bytes (SPDMVersion, RequestResponseCode, Param1, Param2). A literal reading therefore excludes OpaqueDataLength and OpaqueData, even though those fields are transmitted before the trailing signature/HMAC field. Because the signature/HMAC must cover every field transmitted before it to "protect the entire handshake against manipulation by an active attacker," an active attacker could otherwise modify the opaque data in flight without invalidating the signature or HMAC. This issue has been patched in version 1.4.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
First Time appeared Dmtf
Dmtf libspdm
Vendors & Products Dmtf
Dmtf libspdm
Type Values Removed Values Added
Description libspdm is a sample implementation that follows the DMTF SPDM specifications. In version 1.4.0, both the FINISH request (Table 80) and the FINISH_RSP response (Table 81) gained two new fields, OpaqueDataLength and OpaqueData, placed before the trailing signed/authenticated field. The transcript definitions used to compute and verify the FINISH signature, the FINISH HMAC (RequesterVerifyData), and the FINISH_RSP HMAC (ResponderVerifyData) were not updated and still terminate with a step of the form. Per DSP0274, the "SPDM Header Fields" are only the four header bytes (SPDMVersion, RequestResponseCode, Param1, Param2). A literal reading therefore excludes OpaqueDataLength and OpaqueData, even though those fields are transmitted before the trailing signature/HMAC field. Because the signature/HMAC must cover every field transmitted before it to "protect the entire handshake against manipulation by an active attacker," an active attacker could otherwise modify the opaque data in flight without invalidating the signature or HMAC. This issue has been patched in version 1.4.1.
Title libspdm: SPDM (DSP0274) FINISH transcript under-specifies the new 1.4 OpaqueData fields
Weaknesses CWE-325
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Nov 11, 2026, 4:16 AM
Reserved
Jul 10, 2026, 8:17 PM
Status
Deferred
Published
Nov 11, 2026, 5:19 AM
Modified
Nov 12, 2026, 10:11 PM