CVE-2026-61810

MEDIUMCVSS 6/10EPSS 0.14%

Last modified

CVE-2026-61810 is a medium-severity vulnerability rated 6/10 on the CVSS scale. 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. EPSS estimates a 0.14% chance of exploitation in the next 30 days.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
DMTFlibspdm= 1.4.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-61810?
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.
How severe is CVE-2026-61810?
CVE-2026-61810 has a CVSS score of 6/10 (MEDIUM severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.
How do I fix CVE-2026-61810?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST