{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-23T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption",
    "id" : "2461224",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2461224"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-763",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nnet/tls: fix use-after-free in -EBUSY error path of tls_do_encryption\nThe -EBUSY handling in tls_do_encryption(), introduced by commit\n859054147318 (\"net: tls: handle backlogging of crypto requests\"), has\na use-after-free due to double cleanup of encrypt_pending and the\nscatterlist entry.\nWhen crypto_aead_encrypt() returns -EBUSY, the request is enqueued to\nthe cryptd backlog and the async callback tls_encrypt_done() will be\ninvoked upon completion. That callback unconditionally restores the\nscatterlist entry (sge->offset, sge->length) and decrements\nctx->encrypt_pending. However, if tls_encrypt_async_wait() returns an\nerror, the synchronous error path in tls_do_encryption() performs the\nsame cleanup again, double-decrementing encrypt_pending and\ndouble-restoring the scatterlist.\nThe double-decrement corrupts the encrypt_pending sentinel (initialized\nto 1), making tls_encrypt_async_wait() permanently skip the wait for\npending async callbacks. A subsequent sendmsg can then free the\ntls_rec via bpf_exec_tx_verdict() while a cryptd callback is still\npending, resulting in a use-after-free when the callback fires on the\nfreed record.\nFix this by skipping the synchronous cleanup when the -EBUSY async\nwait returns an error, since the callback has already handled\nencrypt_pending and sge restoration.", "A flaw was found in the Linux kernel's `net/tls` component. Incorrect error handling in the `tls_do_encryption()` function, specifically when a cryptographic request returns an error, leads to a double cleanup of internal data structures. This can result in a use-after-free vulnerability, where memory is accessed after it has been deallocated. An attacker could potentially leverage this flaw to cause a denial of service or achieve arbitrary code execution." ],
  "statement" : "Upstream corrected the kTLS encryption error path so -EBUSY handling cannot double-put TLS context state. Red Hat treats this as a local kernel networking/crypto stability issue until product-specific exploitability work completes. Apply patched kernels when released.",
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-31533\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31533\nhttps://lore.kernel.org/linux-cve-announce/2026042309-CVE-2026-31533-9308@gregkh/T" ],
  "name" : "CVE-2026-31533",
  "mitigation" : {
    "value" : "To mitigate this issue, prevent the tls module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.",
    "lang" : "en:us"
  },
  "csaw" : false
}