How severe is CVE-2026-28755?

CVE-2026-28755 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-28755 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-28755?

CVE-2026-28755 primarily affects F5 Nginx Plus. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-28755?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-28755 have an EU (EUVD) identifier?

Yes. CVE-2026-28755 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14887.

When was CVE-2026-28755 published?

CVE-2026-28755 was published on 2026-03-24 and last updated on 2026-06-17.

CVE-2026-28755

CVE-2026-28755 is a medium-severity vulnerability in F5 Nginx Plus with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 5.3
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14887
Weakness: CWE-863
Affected product: F5 Nginx Plus
Published: 2026-03-24
Last modified: 2026-06-17

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_stream_ssl_module module due to the improper handling of revoked certificates when configured with the ssl_verify_client on and ssl_ocsp on directives, allowing the TLS handshake to succeed even after an OCSP check identifies the certificate as revoked. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Frequently asked questions

What is CVE-2026-28755?: NGINX Plus and NGINX Open Source have a vulnerability in the ngx_stream_ssl_module module due to the improper handling of revoked certificates when configured with the ssl_verify_client on and ssl_ocsp on directives, allowing the TLS handshake to succeed even after an OCSP check identifies the certificate as revoked. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
How severe is CVE-2026-28755?: CVE-2026-28755 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-28755 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28755?: CVE-2026-28755 primarily affects F5 Nginx Plus. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-28755?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-28755 have an EU (EUVD) identifier?: Yes. CVE-2026-28755 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14887.
When was CVE-2026-28755 published?: CVE-2026-28755 was published on 2026-03-24 and last updated on 2026-06-17.

References

https://my.f5.com/manage/s/article/K000160368

Affected products (12)

cpe:2.3:a:f5:nginx_plus:r33:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p3:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r35:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:*:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*

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