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GHSA-7XCV-9QFJ-9Q57

Vulnerability from github – Published: 2026-10-28 18:32 – Updated: 2026-10-28 21:31

Details

Impact: The flexible request header is parsed on the network thread before authorization, request dispatch, and request-time quota accounting. A client can send a request of a few tens of megabytes whose header declares about 20 million tagged fields, forcing roughly that many RawTaggedField allocations and exhausting broker heap or inducing process-wide GC stalls, denying broker service. Because the header is parsed for pre-authentication APIs such as ApiVersions (v3), the allocation can occur before authentication; no Kafka resource ACL or quota is required.

Mitigation: Upgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0. Until then, lowering socket.request.max.bytes and restricting network access to broker listeners reduces, but does not remove, exposure.

Resolution: From Apache Kafka 4.2.2, 4.3.2, and 4.4.0: generated readers bounds-check the tagged-field count for flexible-versioned messages, rejecting a negative count, a count exceeding the remaining buffer bytes, or a count exceeding a fixed maximum (10,000), before any per-field allocation.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-111115"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T17:17:38Z",
    "severity": null
  },
  "details": "Apache Kafka\u0027s code-generated readers for flexible protocol versions read a tagged-field count\u00a0declared by the sender and retain a RawTaggedField object for each unknown field. That count\u00a0was bounded only by the outer request frame size (socket.request.max.bytes); it was not checked\u00a0against the remaining buffer bytes or capped. Because each entry can be encoded in as little as\u00a0two bytes (unknown tag 0, size 0), a modest request can declare tens of millions of tagged\u00a0fields and force one object allocation per declared field. Flexible request headers (header\u00a0version 2, used by flexible APIs such as ApiVersions v3) are parsed this way, so the\u00a0amplification applies to the request header itself.\n\n\nImpact:\nThe flexible request header is parsed on the network thread before authorization, request dispatch, and request-time quota accounting. A client can send a request of a few tens of megabytes whose header declares about 20 million tagged fields, forcing roughly that many RawTaggedField allocations and exhausting broker heap or inducing process-wide GC stalls, denying broker service. Because the header is parsed for pre-authentication APIs such as ApiVersions (v3), the allocation can occur before authentication; no Kafka resource ACL or quota is required.\n\nMitigation:\nUpgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0. Until then, lowering socket.request.max.bytes and restricting network access to broker listeners reduces, but does not remove, exposure.\n\nResolution:\nFrom Apache Kafka 4.2.2, 4.3.2, and 4.4.0: generated readers bounds-check the tagged-field count for flexible-versioned messages, rejecting a negative count, a count exceeding the remaining buffer bytes, or a count exceeding a fixed maximum (10,000), before any per-field allocation.",
  "id": "GHSA-7xcv-9qfj-9q57",
  "modified": "2026-10-28T21:31:14Z",
  "published": "2026-10-28T18:32:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111115"
    },
    {
      "type": "WEB",
      "url": "https://kafka.apache.org/cve-list"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/10/28/12"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-111115 (GCVE-0-2026-111115)

Vulnerability from cvelistv5 – Published: 2026-10-28 16:44 – Updated: 2026-10-28 20:06

Title

Apache Kafka: Broker OutOfMemoryError via tagged-field allocation amplification in flexible protocol request parsing

Summary

Apache Kafka's code-generated readers for flexible protocol versions read a tagged-field count declared by the sender and retain a RawTaggedField object for each unknown field. That count was bounded only by the outer request frame size (socket.request.max.bytes); it was not checked against the remaining buffer bytes or capped. Because each entry can be encoded in as little as two bytes (unknown tag 0, size 0), a modest request can declare tens of millions of tagged fields and force one object allocation per declared field. Flexible request headers (header version 2, used by flexible APIs such as ApiVersions v3) are parsed this way, so the amplification applies to the request header itself. Impact: The flexible request header is parsed on the network thread before authorization, request dispatch, and request-time quota accounting. A client can send a request of a few tens of megabytes whose header declares about 20 million tagged fields, forcing roughly that many RawTaggedField allocations and exhausting broker heap or inducing process-wide GC stalls, denying broker service. Because the header is parsed for pre-authentication APIs such as ApiVersions (v3), the allocation can occur before authentication; no Kafka resource ACL or quota is required. Mitigation: Upgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0. Until then, lowering socket.request.max.bytes and restricting network access to broker listeners reduces, but does not remove, exposure. Resolution: From Apache Kafka 4.2.2, 4.3.2, and 4.4.0: generated readers bounds-check the tagged-field count for flexible-versioned messages, rejecting a negative count, a count exceeding the remaining buffer bytes, or a count exceeding a fixed maximum (10,000), before any per-field allocation.

Severity

No CVSS data available.

Assigner

apache CNA under the mitre root

CNA scorecard B 76/100 over 1092 records in the last 180 days details

References

2 references

URL	Tags
https://kafka.apache.org/cve-list	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/1…

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache Kafka	Affected: 2.4.0 , ≤ 4.1.2 (semver) Affected: 4.2.0 , ≤ 4.2.1 (semver) Affected: 4.3.0 , ≤ 4.3.1 (semver)

Credits

Mufeed VH <mufeed@winfunc.com> Vivek R <vivek@winfunc.com> Shay Elkin <selkin@confluent.io>

Show details on NVD website

JSON

To clipboard

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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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