CVE-2026-56434 (GCVE-0-2026-56434)

Vulnerability from cvelistv5 – Published: 2026-07-15 14:33 – Updated: 2026-07-15 18:10
VLAI
Title
NGINX ngx_http_ssi_module vulnerability
Summary
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process. Impact: This vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. 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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
8.3 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-15 15:38 UTC
CWE
Assigner
References
URL Tags
https://my.f5.com/manage/s/article/K000162098 vendor-advisorypatch
Impacted products
Vendor Product Version CPE status
F5 NGINX Plus Affected: 37.0.0.1 , < 37.0.3.1 (custom)
Affected: R36 , < R36 P7 (custom)
Affected: R33 , < * (custom)
guessed Create a notification for this product.
F5 NGINX Open Source Affected: 1.31.2 , < 1.31.3 (custom)
Affected: 0.8.11 , < 1.30.4 (custom)
guessed Create a notification for this product.
Date Public
2026-07-15 14:00
Credits
F5 acknowledges p4p3r(@P4P3R-HAK)" of "싸이버원(CYBERONE) for bringing this issue to our attention and following the highest standards of coordinated disclosure.
Show details on NVD website
To clipboard 

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      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-56434\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-15T15:38:13.231118Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-15T15:38:17.945Z\"}}], \"cna\": {\"title\": \"NGINX ngx_http_ssi_module vulnerability\", \"source\": {\"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"reporter\", \"value\": \"F5 acknowledges p4p3r(@P4P3R-HAK)\\\" of \\\"\\uc2f8\\uc774\\ubc84\\uc6d0(CYBERONE) for bringing this issue to our attention and following the highest standards of coordinated disclosure.\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 6.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}, {\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 8.3, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"LOW\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"HIGH\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"F5\", \"modules\": [\"ngx_http_ssi_module\"], \"product\": \"NGINX Plus\", \"versions\": [{\"status\": \"affected\", \"version\": \"37.0.0.1\", \"lessThan\": \"37.0.3.1\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"R36\", \"lessThan\": \"R36 P7\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"R33\", \"lessThan\": \"*\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}, {\"vendor\": \"F5\", \"modules\": [\"ngx_http_ssi_module\"], \"product\": \"NGINX Open Source\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.31.2\", \"lessThan\": \"1.31.3\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"0.8.11\", \"lessThan\": \"1.30.4\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}], \"datePublic\": \"2026-07-15T14:00:00.000Z\", \"references\": [{\"url\": \"https://my.f5.com/manage/s/article/K000162098\", \"tags\": [\"vendor-advisory\", \"patch\"]}], \"x_generator\": {\"engine\": \"F5 SIRTBot v1.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module\\u00a0module. 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There is no control plane exposure; this is a data plane issue only.\u003cbr\u003e\u003cbr\u003eNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.\u003cbr\u003e\u003cp\u003e\u003c/p\u003e\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab\", \"shortName\": \"f5\", \"dateUpdated\": \"2026-07-15T18:10:54.402Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-56434\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-15T18:10:54.402Z\", \"dateReserved\": \"2026-07-08T15:49:43.050Z\", \"assignerOrgId\": \"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab\", \"datePublished\": \"2026-07-15T14:33:46.142Z\", \"assignerShortName\": \"f5\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.