CVE-2026-59847
published 2026-07-21CVE-2026-59847: A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an…
PriorityP346high7.5CVSS 3.1
AVNACLPRNUINSUCNIHAN
EPSS
0.33%
25.3th percentile
A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| libssh | libssh | — | — |
| libssh | libssh | — | — |
| libssh | libssh | >= 0.9.0 < 0.11.5 | 0.11.5 |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| ubuntu | libssh | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
vendor_ubuntu7.3HIGH
vendor_redhat5.9MEDIUM
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Ubuntu
libssh vulnerabilities
vendor_ubuntu·2026-08-31·CVSS 7.3
CVE-2026-59846 [HIGH] libssh vulnerabilities
Title: libssh vulnerabilities
Summary: Several security issues were fixed in libssh.
It was discovered that libssh had a stack buffer overflow in its SFTP
server when constructing directory listing entries for long filenames. An
attacker could possibly use this issue to cause libssh to crash or execute
arbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-15370)
It was discovered that libssh did not correctly handle SSH channel open
messages advertising a zero maximum packet size. An authenticated remote
attacker could possibly use this issue to cause libssh to consume excessive
CPU resources, leading to a denial of service. (CVE-2026-59843)
It was discovered that libssh did not correctly limit SFTP read request
lengths in its server implementation. An authenticated remo
Red Hat
libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
vendor_redhat·2026-07-21·CVSS 5.9
CVE-2026-59847 [MEDIUM] libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.
Mitigation: Disable the [email protected] and [email protected] ciphers.
Package: libssh (Red Hat Enterprise Linux 10) - Affected
Package: libssh (Red Hat Enterprise Linux 8) - Fix deferred
Package: libssh (Red Hat Enterprise Linux 9) - Affected
Package: libssh (Red Hat Hardened Images) - Affected
GHSA
A flaw was found in libssh.
ghsa_unreviewed·2026-07-21
CVE-2026-59847 [MEDIUM] CWE-1310 A flaw was found in libssh.
A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification [fedora-all]
bugzilla·2026-07-21·CVSS 5.9
CVE-2026-59847 [MEDIUM] CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification [fedora-all]
CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
A flaw was found in libssh builds using the OpenSSL backend for AES-GCM. In the decrypt path in src/libcrypto.c, the return value from EVP_DecryptFinal() was checked incorrectly, so authentication tag verification failures were not handled as integrity failures. This could effectively remove integrity protection for affected AES-GCM sessions and allow an in-path attacker to modify plaintext on the wire without detection.
Bugzilla
CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
bugzilla·2026-07-08·CVSS 5.9
CVE-2026-59847 [MEDIUM] CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
CVE-2026-59847 libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification
A flaw was found in libssh builds using the OpenSSL backend for AES-GCM. In the decrypt path in src/libcrypto.c, the return value from EVP_DecryptFinal() was checked incorrectly, so authentication tag verification failures were not handled as integrity failures. This could effectively remove integrity protection for affected AES-GCM sessions and allow an in-path attacker to modify plaintext on the wire without detection.
2026-07-21
Published