CVE-2026-59843
Low
No strong exploitation signal.
CVSS base
6.5
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS — probability of exploitation (30 days)
0.6%
45.7th percentile
CISA KEV
Not listed
Weakness / dates
CWE-400
Published 2026-07-21 · modified 2026-09-01
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | N | None |
| Integrity | N | None |
| Availability | H | High |
Timeline
- 2026-07-21 — Published (NVD)
- 2026-09-01 — Last modified (NVD)
Description
A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.
Affected
References
- https://access.redhat.com/errata/RHSA-2026:42922
- https://access.redhat.com/errata/RHSA-2026:55855
- https://access.redhat.com/errata/RHSA-2026:62217
- https://access.redhat.com/errata/RHSA-2026:62218
- https://access.redhat.com/security/cve/CVE-2026-59843
- https://bugzilla.redhat.com/show_bug.cgi?id=2498176