CVE-2026-64047

CRITICALCVSS 9.8/10EPSS 0.51%

Last modified

CVE-2026-64047 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

Description

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).

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.51%

40.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 73963a375885d5ccb7def39fd0b4f542e0f343dd; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 47110c3a9ac247b688657337f5981efcfcb240dc; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 84158c2997159df4a0d70cd9c46774512d32a522; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 131ef12057d92b77b636321b7849c69222405a97; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 66339b71f105e6f83e0da3b9583d95077534fe1d; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < eca989eab4b2599dcb02f72140a7c08f08838520; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 2fb0dc7e0099686c4e9d2732745d8a31b18c3628; >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec, < 285943c6e7ca309bbea84b253745154241d9788a; d529d6c9f7e3aaeac13c4948f79799ccb825f29d; >= 5.4.14, < 5.5
LinuxLinux5.5

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64047?
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).
How severe is CVE-2026-64047?
CVE-2026-64047 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.
How do I fix CVE-2026-64047?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST