<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-06-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001076378</issuerCik>
        <issuerName>CEMEX SAB DE CV</issuerName>
        <issuerTradingSymbol>CX</issuerTradingSymbol>
        <issuerForeignTradingSymbol>CEMEX.CPO</issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002074795</rptOwnerCik>
            <rptOwnerName>Ramirez Cantu Alejandro Alberto</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>AVENIDA RICARDO MARGAIN ZOZAYA 325</rptOwnerStreet1>
            <rptOwnerStreet2>COLONIA VALLE DEL CAMPESTRE</rptOwnerStreet2>
            <rptOwnerCity>SAN PEDRO GARZA GARCIA</rptOwnerCity>
            <rptOwnerNonUSStateTerritory>NUEVO LEON</rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>O5</rptOwnerCountry>
            <rptOwnerZipCode>66265</rptOwnerZipCode>
            <rptOwnerStateDescription>MEXICO</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President of Cemex SCA&amp;C</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>CX</value>
            </securityTitle>
            <transactionDate>
                <value>2026-06-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15884</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.25</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>118386</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>CX</value>
            </securityTitle>
            <transactionDate>
                <value>2026-06-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30489</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>148875</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On June 15, 2026, 29,354 American Depositary Shares corresponding to the compensation plans from 2023, 2024 and 2025 vested in favor of the reporting person. Additionally, 543 American Depositary Shares were vested to the reporting person due to a technical adjustment cash dividend, and 592 American Depositary Shares were vested to the reporting person due to a tax adjustment for the 2024 and 2023 compensation plans.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Alejandro Alberto Ramirez Cantu</signatureName>
        <signatureDate>2026-06-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
