# CVE-2026-59997: OpenSSH internal-sftp argument truncation in sshd

Source: https://junglewise.ai/threats/cve-2026-59997-openssh-internal-sftp-argument-truncation-in-sshd  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-08. Updated: 2026-07-08  
License: CC BY 4.0 with a link back

CVE-2026-59997 · Severity: medium · CVSS 4.2 · Published 2026-07-08

OpenSSH is a widely used tool for secure remote access and file transfers. A flaw in its internal SFTP server component causes it to ignore security settings if they are placed too far down in a long list of configuration commands. This could lead to a situation where intended security protections are not actually active, potentially allowing unauthorized file access or other security policy violations.

Technologies: [OpenBSD Openssh](https://junglewise.ai/threats/technologies/openssh). Vendors: [OpenBSD](https://junglewise.ai/threats/vendors/openbsd).

## Quick answers

**Is CVE-2026-59997 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59997 being exploited in the wild.

**How severe is CVE-2026-59997?** Medium severity, with a CVSS score of 4.2, published 8 July 2026.

**Which products and versions are affected?** OpenBSD Openssh before 10.4.

**Is there a fix for CVE-2026-59997?** A patch was published on 2026-07-06: OpenSSH 10.4 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-59997 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59997?** Check whether you run OpenBSD Openssh at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A vulnerability exists in the 'internal-sftp' subsystem of OpenSSH's sshd where command-line arguments are silently truncated after the 9th argument. This is caused by improper validation of the specified quantity of input (CWE-1284). If an administrator configures the internal SFTP server with a long string of arguments where security-critical options (such as read-only mode or path restrictions) appear in the 10th position or later, those options will be discarded. An attacker could exploit this if the lack of these intended security properties allows for unauthorized actions on the SFTP server. This issue is resolved in OpenSSH version 10.4.

## Affected products

- OpenBSD OpenSSH before 10.4

## Timeline

- 2026-07-06: patched: OpenSSH 10.4 released with fix
- 2026-07-08: disclosed: CVE-2026-59997 published

## References

- [https://marc.info/?l=openssh-unix-dev&m=178333966933090&w=2](https://marc.info/?l=openssh-unix-dev&m=178333966933090&w=2)
- [https://www.openssh.org/releasenotes.html](https://www.openssh.org/releasenotes.html)
- [https://www.openwall.com/lists/oss-security/2026/07/06/5](https://www.openwall.com/lists/oss-security/2026/07/06/5)

## Related threats

- [OpenSSH password authentication bypass on musl libc without PAM](https://junglewise.ai/threats/cve-2026-123158-sshd-in-openssh-before-10-6p2-on-linux-when-musl-libc-is-used)
- [In sshd in OpenSSH before 10.5, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not.](https://junglewise.ai/threats/cve-2026-73283-in-sshd-in-openssh-before-10-5-the-restrict-keyword-in-authorized)
- [In ssh in OpenSSH before 10.5, a use-after-free for realloc data can occur if a certain pair of remote-forwarding operations are concurrent.](https://junglewise.ai/threats/cve-2026-73282-in-ssh-in-openssh-before-10-5-a-use-after-free-for-realloc-data)
- [In ssh-agent in OpenSSH before 10.5, some operations can occur remotely but were intended to occur only locally…](https://junglewise.ai/threats/cve-2026-73281-in-ssh-agent-in-openssh-before-10-5-some-operations-can-occur)
- [OpenSSH use-after-free in ssh client during key re-exchange](https://junglewise.ai/threats/cve-2026-60002-openssh-use-after-free-in-ssh-client-during-key-re-exchange)