diff --git a/igvm_defs/src/lib.rs b/igvm_defs/src/lib.rs
index 7d11fd2..8898973 100644
--- a/igvm_defs/src/lib.rs
+++ b/igvm_defs/src/lib.rs
@@ -341,6 +341,14 @@ pub enum IgvmVariableHeaderType {
     /// specified by a structure of type [`IGVM_VHS_PARAMETER`].
     #[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
     IGVM_VHT_ENVIRONMENT_INFO_PARAMETER = 0x313,
+    /// A Corim measurement structure described by [`IGVM_VHS_CORIM_MEASUREMENT`].
+    /// FIXME: should this be an init header to be early in the file?
+    #[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
+    IGVM_VHT_CORIM_MEASUREMENT = 0x314,
+    /// A Corim signature structure described by [`IGVM_VHS_CORIM_SIGNATURE`].
+    /// FIXME: should this be an init header to be early in the file?
+    #[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
+    IGVM_VHT_CORIM_SIGNATURE = 0x315,
 }
 
 /// The range of header types for platform structures.
@@ -1237,3 +1245,57 @@ pub enum VbsSigningAlgorithm {
     /// ECDSA P384.
     ECDSA_P384 = 0x1,
 }
+
+/// A structure defining a CoRIM CBOR payload for a given platform. TODO: rename
+/// to remove measurement?
+///
+/// The payload described by this header is a CBOR CoRIM payload. There may only
+/// be one for a given platform. There may be an associated COSE_Sign1 structure
+/// wrapping this payload, see [`IGVM_VHS_CORIM_SIGNATURE`].
+///
+/// The CoRIM payload must adhere to the following specifications for each
+/// platform:
+///
+/// | Platform | Specification |
+/// |----------|---------------|
+/// | Intel TDX | TBD |
+/// | VBS | TBD |
+/// | AMD SEV-SNP | TBD |
+/// | ARM CCA | TBD |
+#[repr(C)]
+#[derive(Copy, Clone, Debug, IntoBytes, Immutable, KnownLayout, FromBytes)]
+struct IGVM_VHS_CORIM_MEASUREMENT {
+    /// Compatibility mask.
+    pub compatibility_mask: u32,
+    /// File offset for the CoRIM CBOR payload.
+    pub file_offset: u32,
+    /// Size in bytes of the CoRIM CBOR payload.
+    pub size_bytes: u32,
+    /// Reserved.
+    pub reserved: u32,
+}
+
+/// This is a signed COSE_Sign1 structure wrapping a CoRIM CBOR payload for a
+/// given platform. The payload measured by this CBOR is described the
+/// corresponding [`IGVM_VHS_CORIM_MEASUREMENT`] structure. There cannot be this
+/// structure without that one.
+///
+/// Note that a user may choose to create a single CBOR containing this
+/// COSE_Sign1 with the payload filled in by the other corim measurement
+/// structure.
+///
+/// The payload described by this header is a COSE_Sign1 structure described in
+/// section 4.2 in RFC https://datatracker.ietf.org/doc/draft-ietf-rats-corim/,
+/// which is a COSE_Sign1 structure with a CBOR corim payload.
+#[repr(C)]
+#[derive(Copy, Clone, Debug, IntoBytes, Immutable, KnownLayout, FromBytes)]
+struct IGVM_VHS_CORIM_SIGNATURE {
+    /// Compatibility mask.
+    pub compatibility_mask: u32,
+    /// File offset for the COSE_Sign1 measurement payload.
+    pub file_offset: u32,
+    /// Size in bytes of the COSE_Sign1 measurement payload.
+    pub size_bytes: u32,
+    /// Reserved.
+    pub reserved: u32,
+}