# CVE-2026-59847: libssh integrity protection bypass in OpenSSL AES-GCM backend

Source: https://junglewise.ai/threats/cve-2026-59847-libssh-integrity-protection-bypass-in-openssl-aes-gcm-backend  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-21. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-59847 · Severity: medium · CVSS 5.9 · Published 2026-07-21

A security flaw was identified in libssh, a library used by many applications to provide secure communication over the SSH protocol. Due to a coding error in how the library verifies data integrity when using specific encryption settings, a sophisticated attacker positioned between two communicating parties could modify data in transit without being detected. This could lead to the corruption of sensitive information or the injection of malicious commands into a secure session.

Technologies: [Libssh](https://junglewise.ai/threats/technologies/libssh), [Red Hat Enterprise Linux 10](https://junglewise.ai/threats/technologies/enterprise-linux-10), [Red Hat Enterprise Linux 8](https://junglewise.ai/threats/technologies/enterprise-linux-8), [Red Hat Enterprise Linux 9](https://junglewise.ai/threats/technologies/enterprise-linux-9). Vendors: [Libssh](https://junglewise.ai/threats/vendors/libssh), [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-59847 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59847 being exploited in the wild.

**How severe is CVE-2026-59847?** Medium severity, with a CVSS score of 5.9, published 21 July 2026.

**Which products and versions are affected?** Libssh All versions using OpenSSL backend for AES-GCM; Red Hat Enterprise Linux 10 affected status; Red Hat Enterprise Linux 8 affected status; Red Hat Enterprise Linux 9 affected status.

**Is there a fix for CVE-2026-59847?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-59847 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59847?** Check whether you run Libssh, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 or one of the others listed 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 libssh within the `src/libcrypto.c` component when compiled with the OpenSSL backend. The root cause is an incorrect check of the return value from the `EVP_DecryptFinal()` function during AES-GCM decryption. Because authentication tag verification failures are not properly handled as integrity failures, the library fails to detect if the ciphertext has been tampered with. An in-path (man-in-the-middle) attacker can exploit this to modify plaintext on the wire. This requires the session to be using AES-GCM and the library to be linked against OpenSSL.

## Affected products

- libssh libssh All versions using OpenSSL backend for AES-GCM
- Red Hat Red Hat Enterprise Linux 8 affected status
- Red Hat Red Hat Enterprise Linux 9 affected status
- Red Hat Red Hat Enterprise Linux 10 affected status

## Timeline

- 2026-07-08: disclosed: Reported via Red Hat Bugzilla
- 2026-07-21: advisory: NVD and Red Hat published advisory details

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-59847](https://access.redhat.com/security/cve/CVE-2026-59847)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2498180](https://bugzilla.redhat.com/show_bug.cgi?id=2498180)

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