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NVD / CVE Program· CNA Linux

CVE-2026-53267: netfilter: nft_ct: bail out on template ct in get eval

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.12% (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 15bf8091f424f97ed8bfd2385f9fca3203f27be2, 2e154b5f53f1b0b490c7b8b02499f90feb86b1d5, 3027ecbdb5fdf9200251c21d4818e4c447ef78e1; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1.

Low priority for now. Upgrade to Linux Linux 15bf8091f424f97ed8bfd2385f9fca3203f27be2, 2e154b5f53f1b0b490c7b8b02499f90feb86b1d5, 3027ecbdb5fdf9200251c21d4818e4c447ef78e1; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1 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: netfilter: nft_ct: bail out on template ct in get eval I noticed this issue while looking at a historic syzbot report [1]. A rule like the one below is enough to trigger the bug: table ip t { chain pre { type filter hook prerouting priority raw; ct zone set 1 ct original saddr 1.2.3.4 accept } } The first expression attaches a per-cpu template ct via nft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all zero, nf_ct_l3num(ct) == 0). The next expression then calls nft_ct_get_eval() on the same skb, treats the template as a real ct and hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this overflows past struct nft_regs on the kernel stack; with smaller dreg values it silently clobbers adjacent registers. Reject template ct at the eval entry and in nft_ct_get_fast_eval(), mirroring the check nft_ct_set_eval() already has. Additionally, bound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len instead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple before pkt_to_tuple() fills in only the protocol-relevant leading bytes, so the trailing bytes of tuple->{src,dst}.u3.all are well-defined zero. priv->len is validated at rule load, so the copy size is now bounded by the destination register rather than by an untrusted field on the conntrack. [1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jun 25, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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.

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

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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 kernel4.1 and later · before 6.6.143
  • linux linux kernel6.7 and later · before 6.12.94
  • linux linux kernel6.13 and later · before 6.18.36
  • linux linux kernel6.19 and later · before 7.0.13
  • 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

    • 4.1affected
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before 15bf8091f424f97ed8bfd2385f9fca3203f27be2affected · git
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before af80f78ce984649e1698b841cd33f4fa505ad828affected · git
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before 8470f676eadeab99132708acb1a85915664d6115affected · git
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before f071b0bf078146368d18e4eec386bf2ddc0ab7e0affected · git
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before 2e154b5f53f1b0b490c7b8b02499f90feb86b1d5affected · git
    • 45d9bcda21f4c13be75e3571b0f0ef39e77934b5 and later · before 3027ecbdb5fdf9200251c21d4818e4c447ef78e1affected · git
    • before 4.1not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.143 and later · up to and including 6.6.*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 7.0.13-17.0.13-1

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-2026-53264Jun 25, 2026 · net/sched: act_api: use RCU with deferred freeing for action lifecycle
    31Monitor
  • ← EarlierCVE-2026-53265Jun 25, 2026 · dm cache policy smq: check allocation under invalidate lock
    31Monitor
  • Later →CVE-2026-53268Jun 25, 2026 · netfilter: conntrack_irc: fix possible out-of-bounds read
    32Monitor

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 Linux15bf8091f424f97ed8bfd2385f9fca3203f27be2Vendor (CNA)
Linux Linux2e154b5f53f1b0b490c7b8b02499f90feb86b1d5Vendor (CNA)
Linux Linux3027ecbdb5fdf9200251c21d4818e4c447ef78e1Vendor (CNA)
Linux Linux8470f676eadeab99132708acb1a85915664d6115Vendor (CNA)
Linux Linuxaf80f78ce984649e1698b841cd33f4fa505ad828Vendor (CNA)
Linux Linuxf071b0bf078146368d18e4eec386bf2ddc0ab7e0Vendor (CNA)
azl3 kernel 6.6.141.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (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.

  • CVE-2026-4318550 days apartksmbd: fix signededness bug in smb_direct_prepare_negotiation()
    39Monitor
  • CVE-2026-532020 days apartaccel/ivpu: Fix signed integer truncation in IPC receive
    31Monitor
  • CVE-2025-38459335 days apartatm: clip: Fix infinite recursive call of clip_push().
    31Monitor
  • CVE-2026-5339524 days apartnfsd: fix dead ACL conflict guard in nfsd4_create
    30Monitor
  • CVE-2026-533296 days apartdrm/amd/display: Use krealloc_array() in dal_vector_reserve()
    28Monitor
  • CVE-2026-4614928 days apartscsi: target: configfs: Bound snprintf() return in tg_pt_gp_members_show()
    28Monitor

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

Weakness class (CWE)

CWE-674 · Uncontrolled Recursion

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/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.

ATT&CK techniques

—

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