Description
Description
When NGINX Plus or NGINX Open Source is configured with ssl_session_cache

shared:name:size

without an explicit ssl_session_ticket_key file directives to automatically rotate SSL session ticket keys, a remote unauthenticated attacker is able to forge client SSL sessions

in a non-deterministic manner that is beyond the attacker's control. An attacker could leverage this vulnerability to bypass verification of client certificates.

Impact


This vulnerability can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with access to sensitive information. There is no control plane exposure; this is a data plane issue only.






Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Published: 2026-10-14
Score: 8.3 High
EPSS: < 1% Very Low
KEV: No
Impact: Client certificate verification bypass
Action: Apply mitigation
AI Analysis

Impact

The vulnerability arises when NGINX Plus or NGINX Open Source is configured with automatic rotation of SSL session ticket keys without specifying a static ticket key file. A remote, unauthenticated attacker can forge SSL client sessions in a non‑deterministic manner, effectively bypassing the validation of client certificates. This data‑plane flaw exposes resources or functionality to unintended actors, corresponding to the information‑exposure weakness identified as CWE‑908.

Affected Systems

The flaw affects F5:NGINX Open Source and F5:NGINX Plus instances that use the ssl_session_cache shared directive without an explicit ssl_session_ticket_key directive. Versions that have reached end of technical support are not evaluated. Any installation configured in this manner is potentially impacted.

Risk and Exploitability

The CVSS score of 8.3 rates the issue as High severity, yet the EPSS score is missing, suggesting limited known exploitation activity. The vulnerability is not listed in the CISA KEV catalog. The attack vector is remote and unauthenticated, limited to the data plane. An attacker can send traffic to the vulnerable server to generate forged client sessions, bypassing certificate checks and potentially gaining unauthorized access to protected resources or sensitive data.

Generated by OpenCVE AI on October 15, 2026 at 01:13 UTC.

Remediation

Vendor Workaround

Do not enable automatic rotation of SSL session ticket keys: option a) remove the "ssl_session_cache shared:name:size" directive; https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache option b) switch to loading static ticket keys from a file using the "ssl_session_ticket_key" directive. https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key Systems that disable session tickets ("ssl_session_tickets off;") are not affected. https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_tickets

OpenCVE Recommended Actions

  • Configure a static session ticket key with the ssl_session_ticket_key directive and remove the ssl_session_cache shared directive to stop automatic key rotation.
  • Alternatively, load a persistent ticket key from a file using ssl_session_ticket_key and maintain a single key for the server’s lifetime.
  • If session tickets are unnecessary, disable them completely by setting ssl_session_tickets off; which eliminates the vulnerability entirely.

Generated by OpenCVE AI on October 15, 2026 at 01:13 UTC.

Tracking

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Advisories

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History

Thu, 15 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 14 Oct 2026 15:00:00 +0000

Type Values Removed Values Added
Description Description When NGINX Plus or NGINX Open Source is configured with ssl_session_cache shared:name:size without an explicit ssl_session_ticket_key file directives to automatically rotate SSL session ticket keys, a remote unauthenticated attacker is able to forge client SSL sessions in a non-deterministic manner that is beyond the attacker's control. An attacker could leverage this vulnerability to bypass verification of client certificates. Impact This vulnerability can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with access to sensitive information. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Title NGINX ngx_http_ssl_module vulnerability
Weaknesses CWE-908
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N'}

cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: f5

Published:

Updated: 2026-10-15T16:43:47.036Z

Reserved: 2026-09-30T17:31:09.133Z

Link: CVE-2026-97629

cve-icon Vulnrichment

Updated: 2026-10-15T16:38:46.919Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-14T15:17:28.600

Modified: 2026-10-15T17:17:33.410

Link: CVE-2026-97629

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-15T01:15:10Z

Weaknesses
  • CWE-908

    Use of Uninitialized Resource