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NVD / CVE Program· CNA Linux

CVE-2026-23247: tcp: secure_seq: add back ports to TS offset

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 025f532d8c5cfac77845e50daab7f478b360f2ac, 165573e41f2f66ef98940cf65f838b2cb575d9d1, 4.11; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 025f532d8c5cfac77845e50daab7f478b360f2ac, 165573e41f2f66ef98940cf65f838b2cb575d9d1, 4.11; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Mar 18, 2026
Updated
Nov 5, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-23247

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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 kernelafter 4.11 · before 6.18.17
  • linux linux kernel6.19 and later · before 6.19.7
  • linux linux kernel4.10.14
  • linux linux kernel4.11
  • linux linux kernel7.0

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

    • 443fac9f2618b93cbc5ab068dc594530236b3a23, 4.11affected
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before 025f532d8c5cfac77845e50daab7f478b360f2acaffected · git
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before e873e8c16b2fb743a381a9e59c108e63512301ecaffected · git
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before 5da5662181ef8a251e3ba564903002c2e87de452affected · git
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before eae2f14ab2efccdb7480fae7d42c4b0116ef8805affected · git
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before 46e5b0d7cf55821527adea471ffe52a5afbd9cafaffected · git
    • 28ee1b746f493b7c62347d714f58fbf4f70df4f0 and later · before 165573e41f2f66ef98940cf65f838b2cb575d9d1affected · git
    • 4.10.14 and later · before 4.11affected · semver
    • before 4.11not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 6.19.8-16.19.8-1

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-2026-23244Mar 18, 2026 · nvme: fix memory allocation in nvme_pr_read_keys()
    28Monitor
  • ← EarlierCVE-2026-23245Mar 18, 2026 · net/sched: act_gate: snapshot parameters with RCU on replace
    31Monitor
  • Later →CVE-2026-23248Mar 18, 2026 · perf/core: Fix refcount bug and potential UAF in perf_mmap
    31Monitor

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 Linux025f532d8c5cfac77845e50daab7f478b360f2acVendor (CNA)
Linux Linux165573e41f2f66ef98940cf65f838b2cb575d9d1Vendor (CNA)
Linux Linux4.11Vendor (CNA)
Linux Linux46e5b0d7cf55821527adea471ffe52a5afbd9cafVendor (CNA)
Linux Linux5da5662181ef8a251e3ba564903002c2e87de452Vendor (CNA)
Linux Linuxe873e8c16b2fb743a381a9e59c108e63512301ecVendor (CNA)
Linux Linuxeae2f14ab2efccdb7480fae7d42c4b0116ef8805Vendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.94-1 · Debian:13Package 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.

No history yet (it accumulates with the daily EPSS job).

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.

No nightly-computed relations.

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

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 (5 more)

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

All records