CVE-2023-53333

Estado: ModificadaAlta (7.1)—

In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one

Fix this by increasing the stack buffer to also include room for the extra sequence numbers and all the known dccp packet type headers, then pull again after the initial validation of the basic header.

While at it, mark packets invalid that lack 48bit sequence bit but where RFC says the type MUST use them.

Compile tested only.

Heads-up: I intend to remove dccp conntrack support later this year.

Detalles técnicos trazas, registros y código del informe original

Eric Dumazet says:
  nf_conntrack_dccp_packet() has an unique:

  dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);

  And nothing more is 'pulled' from the packet, depending on the content.
  dh->dccph_doff, and/or dh->dccph_x ...)
  So dccp_ack_seq() is happily reading stuff past the _dh buffer.

BUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0
Read of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371
[..]

v2: first skb_header_pointer() now needs to adjust the size to
    only pull the generic header. (Eric)

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 7.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.28%
Percentil entre todas las CVEs puntuadas: 18
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1059 Command and Scripting Interpreterexecution70 %

CWE-125 (out-of-bounds read) en kernel de Linux con AV:L/PR:L/UI:N permite a usuario local leer memoria del kernel y potencialmente ejecutar código; la lectura de buffer stack sin validar dccph_doff/dccph_x expone datos sensibles.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Behavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-125
CWE-125

Referencias

JSON original (NVD)

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one\n\nEric Dumazet says:\n  nf_conntrack_dccp_packet() has an unique:\n\n  dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);\n\n  And nothing more is 'pulled' from the packet, depending on the content.\n  dh->dccph_doff, and/or dh->dccph_x ...)\n  So dccp_ack_seq() is happily reading stuff past the _dh buffer.\n\nBUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0\nRead of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371\n[..]\n\nFix this by increasing the stack buffer to also include room for\nthe extra sequence numbers and all the known dccp packet type headers,\nthen pull again after the initial validation of the basic header.\n\nWhile at it, mark packets invalid that lack 48bit sequence bit but\nwhere RFC says the type MUST use them.\n\nCompile tested only.\n\nv2: first skb_header_pointer() now needs to adjust the size to\n    only pull the generic header. (Eric)\n\nHeads-up: I intend to remove dccp conntrack support later this year."
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