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NVD / CVE Program· CNA Linux

CVE-2026-64047: net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.51% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 131ef12057d92b77b636321b7849c69222405a97, 285943c6e7ca309bbea84b253745154241d9788a, 2fb0dc7e0099686c4e9d2732745d8a31b18c3628.

Low priority for now. Upgrade to Linux Linux 131ef12057d92b77b636321b7849c69222405a97, 285943c6e7ca309bbea84b253745154241d9788a, 2fb0dc7e0099686c4e9d2732745d8a31b18c3628 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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).

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 19, 2026
EPSS
0.5% · 43th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.4.14 and later · before 5.5
  • linux linux kernel5.5.1 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.142
  • linux linux kernel6.7 and later · before 6.12.92
  • linux linux kernel6.13 and later · before 6.18.34
  • linux linux kernel6.19 and later · before 7.0.11
  • linux linux kernel5.5
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • d529d6c9f7e3aaeac13c4948f79799ccb825f29d, 5.5affected
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 73963a375885d5ccb7def39fd0b4f542e0f343ddaffected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 47110c3a9ac247b688657337f5981efcfcb240dcaffected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 84158c2997159df4a0d70cd9c46774512d32a522affected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 131ef12057d92b77b636321b7849c69222405a97affected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 66339b71f105e6f83e0da3b9583d95077534fe1daffected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before eca989eab4b2599dcb02f72140a7c08f08838520affected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 2fb0dc7e0099686c4e9d2732745d8a31b18c3628affected · git
    • 9aaaa56845a06aeabdd597cbe19492dc01f281ec and later · before 285943c6e7ca309bbea84b253745154241d9788aaffected · git
    • 5.4.14 and later · before 5.5affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.12-17.0.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64045Jul 19, 2026 · ovpn: tcp - use cached peer pointer in ovpn_tcp_close()
    33Monitor
  • ← EarlierCVE-2026-64046Jul 19, 2026 · net: tls: prevent chain-after-chain in plain text SG
    39Monitor
  • Later →CVE-2026-64048Jul 19, 2026 · net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux131ef12057d92b77b636321b7849c69222405a97Vendor (CNA)
Linux Linux285943c6e7ca309bbea84b253745154241d9788aVendor (CNA)
Linux Linux2fb0dc7e0099686c4e9d2732745d8a31b18c3628Vendor (CNA)
Linux Linux47110c3a9ac247b688657337f5981efcfcb240dcVendor (CNA)
Linux Linux5.5Vendor (CNA)
Linux Linux66339b71f105e6f83e0da3b9583d95077534fe1dVendor (CNA)
Linux Linux73963a375885d5ccb7def39fd0b4f542e0f343ddVendor (CNA)
Linux Linux84158c2997159df4a0d70cd9c46774512d32a522Vendor (CNA)
Linux Linuxeca989eab4b2599dcb02f72140a7c08f08838520Vendor (CNA)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-5330923 days apartocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison
    39Monitor
  • CVE-2026-5308825 days apartnet: bcmgenet: fix off-by-one in bcmgenet_put_txcb
    39Monitor
  • CVE-2026-5303625 days apartbpf, arm64: Fix off-by-one in check_imm signed range check
    31Monitor
  • CVE-2026-5290740 days apartmedia: rockchip: rkcif: fix off by one bugs
    31Monitor
  • CVE-2024-57990508 days apartwifi: mt76: mt7925: fix off by one in mt7925_load_clc()
    31Monitor
  • CVE-2026-5330623 days aparttty: hvc_iucv: fix off-by-one in number of supported devices
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-193 · Off-by-one Error

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records