packages:
  - module: golang.org/x/crypto
    package: golang.org/x/crypto/salsa20/salsa
    symbols:
      - XORKeyStream
    versions:
      - fixed: 0.0.0-20190320223903-b7391e95e576
    vulnerable_at: 0.0.0-20190313024323-a1f597ede03a
description: |
    XORKeyStream generates incorrect and insecure output for very
    large inputs.

    If more than 256 GiB of keystream is generated, or if the counter
    otherwise grows greater than 32 bits, the amd64 implementation will
    first generate incorrect output, and then cycle back to previously
    generated keystream. Repeated keystream bytes can lead to loss of
    confidentiality in encryption applications, or to predictability
    in CSPRNG applications.

    The issue might affect uses of golang.org/x/crypto/nacl with extremely
    large messages.

    Architectures other than amd64 and uses that generate less than 256 GiB
    of keystream for a single salsa20.XORKeyStream invocation are unaffected.
arch:
  - amd64
cves:
  - CVE-2019-11840
credit: Michael McLoughlin
links:
    pr: https://go.dev/cl/168406
    commit: https://go.googlesource.com/crypto/+/b7391e95e576cacdcdd422573063bc057239113d
    context:
      - https://go.dev/issue/30965
      - https://groups.google.com/g/golang-announce/c/tjyNcJxb2vQ/m/n0NRBziSCAAJ