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NVD / CVE Program· CNA Linux

CVE-2026-53366: ipv4: account for fraggap on the paged allocation path

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: 0.17% (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 5c6375bced6147ec2e460ee3b653f4860d5ecdc2, 77798d7be6ef71e72fb6fc8a2901bf74ebc9706f, a9c24eda24bd15f432e37824e6fc440977cb241c; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.

Low priority for now. Upgrade to Linux Linux 5c6375bced6147ec2e460ee3b653f4860d5ecdc2, 77798d7be6ef71e72fb6fc8a2901bf74ebc9706f, a9c24eda24bd15f432e37824e6fc440977cb241c; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 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: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch is taken, alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap, but the fraggap bytes carried over from the previous skb are copied into the new skb's linear area at offset transhdrlen by the subsequent skb_copy_and_csum_bits(). The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 16, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th 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 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 kernel6.0 and later · before 6.6.144
  • linux linux kernel6.7 and later · before 6.12.95
  • linux linux kernel6.13 and later · before 6.18.38
  • linux linux kernel6.19 and later · before 7.1.3

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

    • 6.0affected
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before 5c6375bced6147ec2e460ee3b653f4860d5ecdc2affected · git
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before ce494707a9c07f27c219ca67f3e138061f53d9b3affected · git
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before a9c24eda24bd15f432e37824e6fc440977cb241caffected · git
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before 77798d7be6ef71e72fb6fc8a2901bf74ebc9706faffected · git
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before c04d9ece23deb9e26c19f9ca215e98b3295aa1bbaffected · git
    • 8eb77cc73977d88787b37c92831b1c242e035396 and later · before eca856950f7cb1a221e02b99d758409f2c5cec42affected · git
    • before 6.0not affected · semver
    • 6.1.178 and later · up to and including 6.1.*not affected · semver
    • 6.6.144 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
AlmaLinux:9kernelbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64kbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debugbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-develbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-devel-matchedbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-modulesbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-extrabefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-develbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-devel-matchedbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-modulesbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-modules-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-64k-modules-extrabefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-abi-stablelistsbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-cross-headersbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debugbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debug-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debug-develbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debug-devel-matchedbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debug-modulesbefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8
AlmaLinux:9kernel-debug-modules-corebefore 5.14.0-687.46.1.el9_85.14.0-687.46.1.el9_8

+96

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-2026-53364Jul 13, 2026 · Bluetooth: hci_conn: Fix memory leak in hci_le_big_terminate()
    22Monitor
  • ← EarlierCVE-2026-53365Jul 13, 2026 · vsock/virtio: fix zerocopy completion for multi-skb sends
    22Monitor
  • Later →CVE-2026-53367Jul 19, 2026 · selinux: fix avdcache auditing
    22Monitor

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 Linux5c6375bced6147ec2e460ee3b653f4860d5ecdc2Vendor (CNA)
Linux Linux77798d7be6ef71e72fb6fc8a2901bf74ebc9706fVendor (CNA)
Linux Linuxa9c24eda24bd15f432e37824e6fc440977cb241cVendor (CNA)
Linux Linuxc04d9ece23deb9e26c19f9ca215e98b3295aa1bbVendor (CNA)
Linux Linuxce494707a9c07f27c219ca67f3e138061f53d9b3Vendor (CNA)
Linux Linuxeca856950f7cb1a221e02b99d758409f2c5cec42Vendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.46.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.177-1 · Debian:12Package registry (OSV)
opensuse:kernel-source7.1.4-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.30.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+16

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-2026-3147885 days apartksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()
    39Monitor
  • CVE-2026-5309122 days apartnet: pull headers in qdisc_pkt_len_segs_init()
    33Monitor
  • CVE-2026-640393 days apartdrm/msm/snapshot: fix dumping of the unaligned regions
    30Monitor
  • CVE-2026-4330269 days apartdrm/v3d: Set DMA segment size to avoid debug warnings
    22Monitor
  • CVE-2025-7128671 days apartASoC: SOF: ipc4-topology: Correct the allocation size for bytes controls
    22Monitor
  • CVE-2026-4310771 days apartxfrm: account XFRMA_IF_ID in aevent size calculation
    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

  • 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-131 · Incorrect Calculation of Buffer Size

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