Vulnerability-Lookup

GHSA-3F65-G3HR-C59R

Vulnerability from github – Published: 2026-10-30 03:32 – Updated: 2026-10-30 03:32

Details

A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.

Severity

6.5 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

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{
  "affected": [],
  "aliases": [
    "CVE-2026-91920"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-30T02:17:10Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.",
  "id": "GHSA-3f65-g3hr-c59r",
  "modified": "2026-10-30T03:32:02Z",
  "published": "2026-10-30T03:32:02Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91920"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-91920"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2528758"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-91920 (GCVE-0-2026-91920)

Vulnerability from cvelistv5 – Published: 2026-10-30 01:16 – Updated: 2026-10-30 01:16

Title

Undertow: undertow: chunkreader message length permits chunk-size overflow

Summary

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

redhat CNA under the redhat root

CNA scorecard B 82/100 over 1086 records in the last 180 days details

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-91920	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2528758	issue-trackingx_refsource_REDHAT

Impacted products

8 products

Vendor	Product	Version
Red Hat	Red Hat build of Apache Camel for Spring Boot 4	cpe:/a:redhat:camel_spring_boot:4
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat Fuse 7	cpe:/a:redhat:jboss_fuse:7
Red Hat	Red Hat JBoss Enterprise Application Platform 7	cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat	Red Hat JBoss Enterprise Application Platform 8	cpe:/a:redhat:jboss_enterprise_application_platform:8
Red Hat	Red Hat JBoss Enterprise Application Platform Expansion Pack	cpe:/a:redhat:jbosseapxp
Red Hat	Red Hat Single Sign-On 7	cpe:/a:redhat:red_hat_single_sign_on:7

Date Public

2026-10-29 12:11

Credits

Red Hat would like to thank Arpit Jain for reporting this issue.

Show details on NVD website

JSON

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          "vendor": "Red Hat"
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          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
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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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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