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             AUSCERT External Security Bulletin Redistribution

                       FreeBSD VuXML: go -- math/big
                             16 November 2020


        AusCERT Security Bulletin Summary

Product:           go
Publisher:         FreeBSD
Operating System:  FreeBSD
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account      
                   Denial of Service               -- Remote/Unauthenticated
                   Reduced Security                -- Existing Account      
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-28367 CVE-2020-28366 CVE-2020-28362

Original Bulletin: 

Comment: This advisory references vulnerabilities in products which run on 
         platforms other than FreeBSD. It is recommended that administrators
         running go check for an updated version of the software for their 
         operating system.

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go -- math/big: panic during recursive division of very large numbers; cmd/go:
arbitrary code execution at build time through cgo

Affected packages
  go < 1.15.5,1


VuXML ID  db4b2f27-252a-11eb-865c-00155d646400
Discovery 2020-11-09
Entry     2020-11-12

The Go project reports:

    A number of math/big.Int methods (Div, Exp, DivMod, Quo, Rem, QuoRem, Mod,
    ModInverse, ModSqrt, Jacobi, and GCD) can panic when provided crafted large
    inputs. For the panic to happen, the divisor or modulo argument must be
    larger than 3168 bits (on 32-bit architectures) or 6336 bits (on 64-bit
    architectures). Multiple math/big.Rat methods are similarly affected.

    Source: https://github.com/golang/go/issues/42552

    The go command may execute arbitrary code at build time when cgo is in use.
    This may occur when running go get on a malicious package, or any other
    command that builds untrusted code. This can be caused by a malicious gcc
    flags specified via a #cgo directive.

    Source: https://github.com/golang/go/issues/42556

    The go command may execute arbitrary code at build time when cgo is in use.
    This may occur when running go get on a malicious package, or any other
    command that builds untrusted code. This can be caused by malicious
    unquoted symbol names.

    Source: https://github.com/golang/go/issues/42559


CVE Name CVE-2020-28362
CVE Name CVE-2020-28366
CVE Name CVE-2020-28367
URL      https://github.com/golang/go/issues/42552
URL      https://github.com/golang/go/issues/42556
URL      https://github.com/golang/go/issues/42559

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