QSN-8563-3: nginx vulnerability
2026-08-19

Summary:
A security issue was fixed in nginx.

Details:
USN-8563-1 fixed vulnerabilities in nginx. The fix for CVE-2026-42533 was
backed out in USN-8563-2 because it could cause a regression. This update
includes a better fix for CVE-2026-42533.

We apologize for the inconvenience.

Original advisory details:

 It was discovered that nginx incorrectly handled certain map directives
 using regex matching and capture variables. A remote attacker could use
 this issue to cause nginx to crash, resulting in a denial of service, or
 possibly execute arbitrary code. (CVE-2026-42533)

 It was discovered that nginx had a use-after-free vulnerability in the
 ngx_http_ssi_module module when configured with Server-Side Includes,
 proxy_pass, and proxy buffering disabled directives. An attacker able to
 intercept traffic and control responses from an upstream server could
 possibly use this issue to cause nginx to crash, resulting in a denial of
 service. (CVE-2026-56434)

 It was discovered that nginx incorrectly handled certain requests in the
 ngx_http_slice_module module. A remote attacker could possibly use this
 issue to obtain sensitive information or cause nginx to crash, resulting
 in a denial of service. (CVE-2026-60005)

Affected QuantaStor releases:
  6.9.1.001 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.22 (fixed in 1.18.0-6ubuntu14.19)
  6.9.1.001 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.22 (fixed in 1.18.0-6ubuntu14.19)
  6.9.1.001 jammy: nginx-common 1.18.0-6ubuntu14.22 (fixed in 1.18.0-6ubuntu14.19)
  6.9.1.001 jammy: nginx-light 1.18.0-6ubuntu14.22 (fixed in 1.18.0-6ubuntu14.19)
  6.9.0.464 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.21 (fixed in 1.18.0-6ubuntu14.19)
  6.9.0.464 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.21 (fixed in 1.18.0-6ubuntu14.19)
  6.9.0.464 jammy: nginx-common 1.18.0-6ubuntu14.21 (fixed in 1.18.0-6ubuntu14.19)
  6.9.0.464 jammy: nginx-light 1.18.0-6ubuntu14.21 (fixed in 1.18.0-6ubuntu14.19)
  6.8.6.015 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.20 (fixed in 1.18.0-6ubuntu14.19)
  6.8.6.015 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.20 (fixed in 1.18.0-6ubuntu14.19)
  6.8.6.015 jammy: nginx-common 1.18.0-6ubuntu14.20 (fixed in 1.18.0-6ubuntu14.19)
  6.8.6.015 jammy: nginx-light 1.18.0-6ubuntu14.20 (fixed in 1.18.0-6ubuntu14.19)
  6.8.5.018 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.5.018 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.5.018 jammy: nginx-common 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.5.018 jammy: nginx-light 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.4.038 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.4.038 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.4.038 jammy: nginx-common 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.4.038 jammy: nginx-light 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.3.018 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.3.018 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.3.018 jammy: nginx-common 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.3.018 jammy: nginx-light 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.2.002 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.2.002 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.2.002 jammy: nginx-common 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.2.002 jammy: nginx-light 1.18.0-6ubuntu14.18 (fixed in 1.18.0-6ubuntu14.19)
  6.8.1.007 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.1.007 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.1.007 jammy: nginx-common 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.1.007 jammy: nginx-light 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.0.205 jammy: libnginx-mod-http-echo 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.0.205 jammy: libnginx-mod-http-geoip2 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.0.205 jammy: nginx-common 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)
  6.8.0.205 jammy: nginx-light 1.18.0-6ubuntu14.16 (fixed in 1.18.0-6ubuntu14.19)

CVEs: CVE-2026-42533

References:
  https://ubuntu.com/security/notices/USN-8563-3