CVE-2026-97629: NGINX ngx_http_ssl_module vulnerability
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.2%
EPSS score, percentile 13.9 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 8.3 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
- Which versions are affected?
Affected
- from 37.1.0 to before 37.1.0.1
- from 37.0.0 to before 37.0.5.1
- R36
- R35
- R34
- R33
and 3 more in the table below
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Workaround (from the CVE record)
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
Advisories and patches
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | from 37.1.0 to before 37.1.0.1 |
| Affected | from 37.0.0 to before 37.0.5.1 |
| Affected | R36 |
| Affected | R35 |
| Affected | R34 |
| Affected | R33 |
Versions not listed are: unknown.
| Status | Versions |
|---|---|
| Affected | from 1.31.0 to before 1.31.7 |
| Affected | from 1.30.0 to before 1.30.6 |
| Affected | 1.23.3 |
Versions not listed are: unknown.
Source: CVE List, as of . About the data.
About this vulnerability
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 vulnerabili…
Summary: CVE record, as of .
- CISA has not added CVE-2026-97629 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 14 Oct 2026.
- The CVE record carries a CVSS v4.0 base score of 8.3 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.2% (percentile 13.9), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
- The credits in the CVE record name Anthropic (Claude) as finder.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
NGINX ngx_http_ssl_module vulnerability
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.
Source: CVE List, as of . About the data.
Weakness
CWE-908, 1 CAPEC
- CWE-908: Use of Uninitialized Resource
Attack patterns (CAPEC)
- CAPEC-59: Session Credential Falsification through Prediction
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
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