openssh: Use of Uninitialized Resource
CVE-2026-3497 is a high-severity use of uninitialized resource vulnerability in openssh from Ubuntu, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 1:10.0p1-5ubuntu5.1, 1:9.6p1-3ubuntu13.15, 1:8.9p1-3ubuntu0.14 as the first without the flaw, so updating openssh to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.38% chance of exploitation within 30 days, higher than 84% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update openssh to 1:10.0p1-5ubuntu5.1 or 1:9.6p1-3ubuntu13.15 or 1:8.9p1-3ubuntu0.14, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 17 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.9 | Medium | CNA (ubuntu.com) |
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 8.2 | High | CNA |
Official description
Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself. The usage of sshpkt_disconnect() on an error, which does not terminate the process, allows an attacker to send an unexpected GSSAPI message type during the GSSAPI key exchange to the server, which will call the underlying function and continue the execution of the program without setting the related connection variables. As the variables are not initialized to NULL the code later accesses those uninitialized variables, accessing random memory, which could lead to undefined behavior. The recommended workaround is to use ssh_packet_disconnect() instead, which does terminate the process. The impact of the vulnerability depends heavily on the compiler flag hardening configuration.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Uninitialized Resource
The product uses or accesses a resource that has not been initialized.
How developers prevent this class of flaw
- Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.
- Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.
- Avoid race conditions (CWE-362) during initialization routines.
More Use of Uninitialized Resource vulnerabilities (CWE-908)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- ubuntu.com/security/CVE-2026-3497Third Party Advisory
- openwall.com/lists/oss-security/2026/03/12/3Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/12/3Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/14/3Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/14/4Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/18/2Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/18/4Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/18/5Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/03/18/7Mailing List, Third Party Advisory
- lists.debian.org/debian-lts-announce/2026/04/msg00014.htmlMailing List, Third Party Advisory
Other references
- access.redhat.com/errata/RHSA-2026:10065
- access.redhat.com/errata/RHSA-2026:10714
- access.redhat.com/errata/RHSA-2026:12071
- access.redhat.com/errata/RHSA-2026:13750
- access.redhat.com/errata/RHSA-2026:13812
- access.redhat.com/errata/RHSA-2026:14773
- access.redhat.com/errata/RHSA-2026:14924
- access.redhat.com/errata/RHSA-2026:15087
- access.redhat.com/errata/RHSA-2026:15891
- access.redhat.com/errata/RHSA-2026:15893
- access.redhat.com/errata/RHSA-2026:16008
- access.redhat.com/errata/RHSA-2026:16009
- access.redhat.com/errata/RHSA-2026:16030
- access.redhat.com/errata/RHSA-2026:16174
- access.redhat.com/errata/RHSA-2026:17596
Recent Use of Uninitialized Resource vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 8.7 High severity
- 8.7 High severity
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