5.4

CVE-2026-28755: f5 nginx open source Incorrect Authorization

CVSS: 5.4v3.1MediumAnalyzed
AliasesALPINE-CVE-2026-28755UBUNTU-CVE-2026-28755DEBIAN-CVE-2026-28755
Published 24-03-2026Last modified 24-03-2026
Open JSON

Vulnerability summary

CVE-2026-28755 is a medium (CVSS 5.4) Incorrect Authorization vulnerability in f5 nginx open source. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 4.2% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.15%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 3
MGASA-2026-0111OPENSUSE-SU-2026:10423-1RHSA-2026:8346CGA-5QGP-XM36-JRQ2USN-8210-1

Timeline

  1. 24-03-2026
    PublishedVulnerability first disclosed.
  2. 24-03-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

10 scores · 7 sources · 2 versions

EPSS trend

Probability

0.15%

Chance of exploitation in the next 30 days

Percentile

4%

Versus all other CVEs

30-day change

+0.02 pp

From 0.13% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.15%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard2 products
  • nginx-mainline< 1.29.7-r0
  • nginx-stable< 1.28.3-r0
F52 products
  • nginx open source≥ 0.5.13, ≤ 0.9.7 | ≥ 1.27.2, < 1.28.3 | ≥ 1.29.0, < 1.29.7
  • nginx plus≥ R36, < R36 P3 | ≥ R35, < R35 P2 | ≥ R34 (No fix recorded) | ≥ R33 (No fix recorded) | r33 | r33:p1 | r33:p2 | r33:p3 | r34 | r34:p1 | r34:p2 | r35:p1 | r36 | r36:p1 | r36:p2
Wolfi2 products
  • nginx-mainline< 1.29.7-r0
  • nginx-stable< 1.28.3-r0
Alpine1 product
  • nginx< 1.28.3-r0
Debian1 product
  • nginx< 1.28.3-2
Ubuntu1 product
  • nginx< 1.24.0-2ubuntu7.7 | < 1.28.0-6ubuntu1.2

6 vendors · 9 products

References

7 links