{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "5800b1cf3fd8ccab752a101865be1e76dac33142"
            },
            {
              "fixed": "9132b1a7bf83b4a8042fffbc99d075b727a16742"
            },
            {
              "fixed": "20386e7f8d97475b8d815873e246423317ec4260"
            },
            {
              "fixed": "b33f5741bb187db8ff32e8f5b96def77cc94dfca"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.16.0"
            },
            {
              "fixed": "6.18.23"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31640.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix use of wrong skb when comparing queued RESP challenge serial\n\nIn rxrpc_post_response(), the code should be comparing the challenge serial\nnumber from the cached response before deciding to switch to a newer\nresponse, but looks at the newer packet private data instead, rendering the\ncomparison always false.\n\nFix this by switching to look at the older packet.\n\nFix further[1] to substitute the new packet in place of the old one if\nnewer and also to release whichever we don't use.",
  "id": "CVE-2026-31640",
  "modified": "2026-07-08T05:37:07.217646714Z",
  "published": "2026-04-24T14:44:54.024Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/20386e7f8d97475b8d815873e246423317ec4260"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9132b1a7bf83b4a8042fffbc99d075b727a16742"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b33f5741bb187db8ff32e8f5b96def77cc94dfca"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31640.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31640"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "rxrpc: Fix use of wrong skb when comparing queued RESP challenge serial"
}