CVE-2026-49423 (GCVE-0-2026-49423)

Vulnerability from cvelistv5 – Published: 2026-08-19 07:01 – Updated: 2026-08-19 07:01
VLAI
Title
Remote DOS via uninitialized memory access in KTLS receive
Summary
When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes. This left uninitialized entries in the iovec array. The iovec array was allocated without zeroing. A remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic. The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header.
Severity
No CVSS data available.
CWE
  • CWE-908 - Use of Uninitialized Resource
Assigner
References
Impacted products
Vendor Product Version CPE status
FreeBSD FreeBSD Affected: 15.1-RELEASE , < p1 (release)
Affected: 15.0-RELEASE , < p11 (release)
Affected: 14.4-RELEASE , < p7 (release)
Affected: 14.3-RELEASE , < p16 (release)
guessed Create a notification for this product.
Date Public
2026-06-30 20:00
Credits
Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "ktls"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p1",
              "status": "affected",
              "version": "15.1-RELEASE",
              "versionType": "release"
            },
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              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            },
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              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p16",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai"
        }
      ],
      "datePublic": "2026-06-30T20:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes.  This left uninitialized entries in the iovec array.  The iovec array was allocated without zeroing.\n\nA remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic.  The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-908",
              "description": "CWE-908: Use of Uninitialized Resource",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T07:01:49.801Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:46.ktls.asc"
        }
      ],
      "title": "Remote DOS via uninitialized memory access in KTLS receive",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
    "assignerShortName": "freebsd",
    "cveId": "CVE-2026-49423",
    "datePublished": "2026-08-19T07:01:49.801Z",
    "dateReserved": "2026-05-29T20:24:28.616Z",
    "dateUpdated": "2026-08-19T07:01:49.801Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-49423",
      "date": "2026-08-25",
      "epss": "0.0015",
      "percentile": "0.04444"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-49423\",\"sourceIdentifier\":\"secteam@freebsd.org\",\"published\":\"2026-08-19T07:16:28.570\",\"lastModified\":\"2026-08-19T07:16:28.570\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes.  This left uninitialized entries in the iovec array.  The iovec array was allocated without zeroing.\\n\\nA remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic.  The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header.\"}],\"affected\":[{\"source\":\"secteam@freebsd.org\",\"affectedData\":[{\"vendor\":\"FreeBSD\",\"product\":\"FreeBSD\",\"defaultStatus\":\"unknown\",\"modules\":[\"ktls\"],\"versions\":[{\"version\":\"15.1-RELEASE\",\"lessThan\":\"p1\",\"versionType\":\"release\",\"status\":\"affected\"},{\"version\":\"15.0-RELEASE\",\"lessThan\":\"p11\",\"versionType\":\"release\",\"status\":\"affected\"},{\"version\":\"14.4-RELEASE\",\"lessThan\":\"p7\",\"versionType\":\"release\",\"status\":\"affected\"},{\"version\":\"14.3-RELEASE\",\"lessThan\":\"p16\",\"versionType\":\"release\",\"status\":\"affected\"}]}]}],\"metrics\":{},\"weaknesses\":[{\"source\":\"secteam@freebsd.org\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-908\"}]}],\"references\":[{\"url\":\"https://security.freebsd.org/advisories/FreeBSD-SA-26:46.ktls.asc\",\"source\":\"secteam@freebsd.org\"}]}}"
  }
}



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