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Fencer Vulns
medium 5.8

CVE-2026-42926 json

NGINX ngx_http_proxy_v2_module vulnerability

published 2026-05-13 5 mo ago modified 2026-10-26 13 d ago also BIT-nginx-2026-42926 , BIT-nginx-gateway-2026-42926 , EUVD-2026-30006

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Patch / fix

  • bitnami nginx 1.30.1
  • bitnami nginx-gateway 1.30.1
  • F5 NGINX Open Source 1.30.1, 1.31.0
  • nginx Debian 14 1.30.0-4

debian advisories DEBIAN-CVE-2026-42926

  • nginx hummingbird 1 1.30.2-1.hum1
  • nginx-core hummingbird 1 1.30.2-1.hum1
  • nginx-mod-mail hummingbird 1 1.30.2-1.hum1
  • nginx-filesystem hummingbird 1 1.30.2-1.hum1
  • nginx-mod-stream hummingbird 1 1.30.2-1.hum1
  • nginx-all-modules hummingbird 1 1.30.2-1.hum1
  • nginx-mod-http-perl hummingbird 1 1.30.2-1.hum1
  • nginx-mod-http-geoip hummingbird 1 1.30.2-1.hum1

red hat advisories RHSA-2026:20351

  • nginx openSUSE Tumbleweed 1.31.0-1.1

opensuse advisories openSUSE-SU-2026:10796-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42926 updated cvss 5.8

nginx: NGINX Open Source: Data injection via HTTP/2 proxy configuration

  • Red Hat Enterprise Linux 8 nginx, nginx-mod-mail, nginx-filesystem, nginx-mod-stream, nginx-all-modules, nginx-mod-http-perl, +2 more Red Hat Enterprise Linux 9 nginx, nginx-core, nginx-mod-mail, nginx-filesystem, nginx-mod-stream, nginx-all-modules, +3 more Red Hat Enterprise Linux 10 nginx
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images nginx 1.30.2-1.hum1, nginx-core 1.30.2-1.hum1, nginx-mod-mail 1.30.2-1.hum1, nginx-filesystem 1.30.2-1.hum1, nginx-mod-stream 1.30.2-1.hum1, nginx-all-modules 1.30.2-1.hum1, +5 more
    fixed: vendor fix RHSA-2026:20351

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
bitnami nginx
>=1.29.4, <1.30.1
1.30.1
bitnami nginx-gateway
>=1.29.4, <1.30.1
1.30.1

Affected products

  • F5 NGINX Open Source

Classification

Weakness
  • CWE-172 Improper Encoding or Decoding of Data
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.