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CVE-2026-64047

9.8 critical SSVC exploitation: none Modified

In the Linux kernel, the following vulnerability has been resolved: net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring When an sk_msg scatterlist ring wraps (sg.end < sg.start), tls_push_record() chains the tail portion of the ring to the head using sg_chain(). An extra entry in the sg array is reserved for this: struct sk_msg_sg { [...] /* The extra two elements: * 1) used for chaining the front and sections when the list becomes * partitioned (e.g. end < start). The crypto APIs require the * chaining; * 2) to chain tailer SG entries after the message. */ struct scatterlist data[MAX_MSG_FRAGS + 2]; The current code uses MAX_SKB_FRAGS + 1 as the ring size: sg_chain(&msg_pl->sg.data[msg_pl->sg.start], MAX_SKB_FRAGS - msg_pl->sg.start + 1, msg_pl->sg.data); This places the chain pointer at sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. = &data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 = data[start + (MAX_SKB_FRAGS - start + 1) - 1] = data[MAX_SKB_FRAGS] instead of the true last entry. This is likely due to a "race" of the commit under Fixes landing close to commit 031097d9e079 ("bpf: sk_msg, zap ingress queue on psock down") Convert to ARRAY_SIZE and drop the data[start] / - start (as suggested by Sabrina).

Fix

Patch, vendor advisory and mitigation references on NVD 8

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 3

  1. CwesCWE-193 → CWE-193, CWE-191NVD modified 2026-10-19 21:17
  2. StatusAnalyzed → ModifiedNVD modified 2026-10-19 21:17
  3. First seenCVSS 9.8 · linuxNVD modified 2026-10-16 16:19

Affected (CPE criteria) 6

  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:5.5:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:5.5:rc7:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*

References 8