Vulnerability-Lookup

RHSA-2026:73135

Vulnerability from csaf_redhat - Published: 2026-09-29 11:10 - Updated: 2026-11-07 05:51

Summary

Red Hat Security Advisory: Red Hat Ansible Automation Platform Execution Environments Update

Severity

Important

Notes

Topic: An update is now available for Red Hat Ansible Automation Platform Execution Environments

Details: Red Hat Ansible Automation Platform provides an enterprise framework for building, deploying and managing IT automation at scale. IT Managers can provide top-down guidelines on how automation is applied to individual teams, while automation developers retain the freedom to write tasks that leverage existing knowledge without the overhead. Ansible Automation Platform makes it possible for users across an organization to share, vet, and manage automation content by means of a simple, powerful, and agentless language. Update(s) and Fix(es): * Update ansible-core to 2.18.19 * Dependency updates (including urllib3)

Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

CVE-2025-66418

A flaw was found in urllib3 Python library that could lead to a Denial of Service condition. A remote, malicious server can exploit this flaw by responding to a client request with an HTTP message that uses an excessive number of chained compression algorithms. This unlimited decompression chain causes the client system to consume a virtually unbounded amount of CPU resources and memory. The high resource usage leads to service disruption, making the application unresponsive.

7.5 (High)


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

CWE-770 - Allocation of Resources Without Limits or Throttling

Affected products

Fixed 4 products

Product	Version	Remediation
Unresolved product id: Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:2411951fcea745a08e40e29e85ab236961ddbf785941d157d307d1bc32801b00_s390x	—	Vendor Fix fix Workaround
Unresolved product id: Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:46c24edb3f9f7af66cfd748f53b561672b0e82b8add3c11e0d868338bc75b3da_arm64	—	Vendor Fix fix Workaround
Unresolved product id: Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:a44c41e3ea316ef99719d2b80e4daf0901158b49e58b6c47e41d4e3f8e359a04_ppc64le	—	Vendor Fix fix Workaround
Unresolved product id: Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:dbf9d0fd58d25101e659666417bcb27dcd1dcd2af83df34f0d3af952e3227ff6_amd64	—	Vendor Fix fix Workaround

Threats

Impact Important

References

10 references

URL	Category
https://access.redhat.com/errata/RHSA-2026:73135	self
https://access.redhat.com/security/cve/CVE-2025-66418	external
https://access.redhat.com/security/updates/classi…	external
https://security.access.redhat.com/data/csaf/v2/a…	self
https://access.redhat.com/security/cve/CVE-2025-66418	self
https://bugzilla.redhat.com/show_bug.cgi?id=2419455	external
https://www.cve.org/CVERecord?id=CVE-2025-66418	external
https://nvd.nist.gov/vuln/detail/CVE-2025-66418	external
https://github.com/urllib3/urllib3/commit/24d7b67…	external
https://github.com/urllib3/urllib3/security/advis…	external

JSON

To clipboard

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      "cwe": {
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        "name": "Allocation of Resources Without Limits or Throttling"
      },
      "discovery_date": "2025-12-05T17:01:20.277857+00:00",
      "ids": [
        {
          "system_name": "Red Hat Bugzilla ID",
          "text": "2419455"
        }
      ],
      "notes": [
        {
          "category": "description",
          "text": "A flaw was found in urllib3 Python library that could lead to a Denial of Service condition. A remote, malicious server can exploit this flaw by responding to a client request with an HTTP message that uses an excessive number of chained compression algorithms. This unlimited decompression chain causes the client system to consume a virtually unbounded amount of CPU resources and memory. The high resource usage leads to service disruption, making the application unresponsive.",
          "title": "Vulnerability description"
        },
        {
          "category": "summary",
          "text": "urllib3: urllib3: Unbounded decompression chain leads to resource exhaustion",
          "title": "Vulnerability summary"
        },
        {
          "category": "other",
          "text": "This Important impact denial of service vulnerability in the urllib3 HTTP client library allows uncontrolled memory consumption when decompressing highly compressed HTTP responses. Due to the lack of an overall decompression size limit in the Streaming API, a malicious server can exhaust client memory, leading to a denial of service.",
          "title": "Statement"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product\u0027s status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
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          "url": "https://access.redhat.com/errata/RHSA-2026:73135"
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      "scores": [
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            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:2411951fcea745a08e40e29e85ab236961ddbf785941d157d307d1bc32801b00_s390x",
            "Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:46c24edb3f9f7af66cfd748f53b561672b0e82b8add3c11e0d868338bc75b3da_arm64",
            "Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:a44c41e3ea316ef99719d2b80e4daf0901158b49e58b6c47e41d4e3f8e359a04_ppc64le",
            "Red Hat Ansible Automation Platform 2.18:registry.redhat.io/ansible-automation-platform/ee-minimal-rhel8@sha256:dbf9d0fd58d25101e659666417bcb27dcd1dcd2af83df34f0d3af952e3227ff6_amd64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ],
      "title": "urllib3: urllib3: Unbounded decompression chain leads to resource exhaustion"
    }
  ]
}

CVE-2025-66418 (GCVE-0-2025-66418)

Vulnerability from cvelistv5 – Published: 2025-12-05 16:02 – Updated: 2025-12-05 18:15

Title

urllib3 allows an unbounded number of links in the decompression chain

Summary

urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0.

Severity

8.9 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-12-05 16:15 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7877 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/urllib3/urllib3/security/advis…	x_refsource_CONFIRM
https://github.com/urllib3/urllib3/commit/24d7b67…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
urllib3	urllib3	Affected: >= 1.24, < 2.6.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-66418",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-12-05T16:15:39.701596Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-12-05T16:16:08.790Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "product": "urllib3",
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            {
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            }
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        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 8.9,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
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          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
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      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-05T18:15:28.505Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      },
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          "tags": [
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        },
        {
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          "tags": [
            "x_refsource_MISC"
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      "source": {
        "advisory": "GHSA-gm62-xv2j-4w53",
        "discovery": "UNKNOWN"
      },
      "title": "urllib3 allows an unbounded number of links in the decompression chain"
    }
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    "assignerShortName": "GitHub_M",
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    "datePublished": "2025-12-05T16:02:15.271Z",
    "dateReserved": "2025-11-28T23:33:56.367Z",
    "dateUpdated": "2025-12-05T18:15:28.505Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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