MSRC_CVE-2026-3904

Vulnerability from csaf_microsoft - Published: 2026-03-13 01:03 - Updated: 2026-03-27 01:38
Summary
Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the GNU C Library version 2.36 under high load on x86_64 systems, the client may call memcmp on inputs that are concurrently modified by other processes or threads and crash. The nscd client in the GNU C Library uses the memcmp function with inputs that may be concurrently modified by another thread, potentially resulting in spurious cache misses, which in itself is not a security issue.  However in the GNU C Library version 2.36 an optimized implementation of memcmp was introduced for x86_64 which could crash when invoked with such undefined behaviour, turning this into a potential crash of the nscd client and the application that uses it. This implementation was backported to the 2.35 branch, making the nscd client in that branch vulnerable as well.  Subsequently, the fix for this issue was backported to all vulnerable branches in the GNU C Library repository. It is
Notes
Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
CVE-2026-3904
CWE-366 - Race Condition within a Thread
Affected products
Product Identifier Version Remediation
Unresolved product id: 17086-1 —
References
To clipboard 

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
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    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-3904 Calling NSS-backed functions that support caching via nscd may call the \nnscd client side code and in the GNU C Library version 2.36 under high \nload on x86_64 systems, the client may call memcmp on inputs that are \nconcurrently modified by other processes or threads and crash.\n\n\n\n\nThe nscd client in the GNU C Library uses the memcmp function with \ninputs that may be concurrently modified by another thread, potentially \nresulting in spurious cache misses, which in itself is not a security \nissue.\u00a0 However in the GNU C Library version 2.36 an optimized \nimplementation of memcmp was introduced for x86_64 which could crash \nwhen invoked with such undefined behaviour, turning this into a \npotential crash of the nscd client and the application that uses it. \nThis implementation was backported to the 2.35 branch, making the nscd \nclient in that branch vulnerable as well.\u00a0 Subsequently, the fix for \nthis issue was backported to all vulnerable branches in the GNU C \nLibrary repository.\n\n\nIt is - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-3904.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Calling NSS-backed functions that support caching via nscd may call the \nnscd client side code and in the GNU C Library version 2.36 under high \nload on x86_64 systems, the client may call memcmp on inputs that are \nconcurrently modified by other processes or threads and crash.\n\n\n\n\nThe nscd client in the GNU C Library uses the memcmp function with \ninputs that may be concurrently modified by another thread, potentially \nresulting in spurious cache misses, which in itself is not a security \nissue.\u00a0 However in the GNU C Library version 2.36 an optimized \nimplementation of memcmp was introduced for x86_64 which could crash \nwhen invoked with such undefined behaviour, turning this into a \npotential crash of the nscd client and the application that uses it. \nThis implementation was backported to the 2.35 branch, making the nscd \nclient in that branch vulnerable as well.\u00a0 Subsequently, the fix for \nthis issue was backported to all vulnerable branches in the GNU C \nLibrary repository.\n\n\nIt is",
    "tracking": {
      "current_release_date": "2026-03-27T01:38:14.000Z",
      "generator": {
        "date": "2026-10-02T07:00:42.769Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-3904",
      "initial_release_date": "2026-03-13T01:03:00.000Z",
      "revision_history": [
        {
          "date": "2026-03-13T01:03:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-03-27T01:38:14.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "category": "product_name",
            "name": "cbl2 glibc 0:2.35-10.cbl2",
            "product": {
              "name": "cbl2 glibc 0:2.35-10.cbl2",
              "product_id": "1"
            }
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 glibc 0:2.35-10.cbl2 as a component of CBL Mariner 2.0",
          "product_id": "17086-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-3904",
      "cwe": {
        "id": "CWE-366",
        "name": "Race Condition within a Thread"
      },
      "flags": [
        {
          "label": "component_not_present",
          "product_ids": [
            "17086-1"
          ]
        }
      ],
      "notes": [
        {
          "category": "general",
          "text": "glibc",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_not_affected": [
          "17086-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-3904 Calling NSS-backed functions that support caching via nscd may call the \nnscd client side code and in the GNU C Library version 2.36 under high \nload on x86_64 systems, the client may call memcmp on inputs that are \nconcurrently modified by other processes or threads and crash.\n\n\n\n\nThe nscd client in the GNU C Library uses the memcmp function with \ninputs that may be concurrently modified by another thread, potentially \nresulting in spurious cache misses, which in itself is not a security \nissue.\u00a0 However in the GNU C Library version 2.36 an optimized \nimplementation of memcmp was introduced for x86_64 which could crash \nwhen invoked with such undefined behaviour, turning this into a \npotential crash of the nscd client and the application that uses it. \nThis implementation was backported to the 2.35 branch, making the nscd \nclient in that branch vulnerable as well.\u00a0 Subsequently, the fix for \nthis issue was backported to all vulnerable branches in the GNU C \nLibrary repository.\n\n\nIt is - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-3904.json"
        }
      ],
      "title": "Calling NSS-backed functions that support caching via nscd may call the \nnscd client side code and in the GNU C Library version 2.36 under high \nload on x86_64 systems, the client may call memcmp on inputs that are \nconcurrently modified by other processes or threads and crash.\n\n\n\n\nThe nscd client in the GNU C Library uses the memcmp function with \ninputs that may be concurrently modified by another thread, potentially \nresulting in spurious cache misses, which in itself is not a security \nissue.\u00a0 However in the GNU C Library version 2.36 an optimized \nimplementation of memcmp was introduced for x86_64 which could crash \nwhen invoked with such undefined behaviour, turning this into a \npotential crash of the nscd client and the application that uses it. \nThis implementation was backported to the 2.35 branch, making the nscd \nclient in that branch vulnerable as well.\u00a0 Subsequently, the fix for \nthis issue was backported to all vulnerable branches in the GNU C \nLibrary repository.\n\n\nIt is"
    }
  ]
}



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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.