NVD / CVE Program· CNA Linux

CVE-2026-53228: ipv6: sit: reload inner IPv6 header after GSO offloads

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: 0.57% (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 0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0, 1132e5edc2866c3530be17622153a597095f0e43, 2fa49b2715e1bad12ce3b0fa64e234d9582c8193; 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 0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0, 1132e5edc2866c3530be17622153a597095f0e43, 2fa49b2715e1bad12ce3b0fa64e234d9582c8193; 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: ipv6: sit: reload inner IPv6 header after GSO offloads ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function entry and continues using it after iptunnel_handle_offloads(). For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone(). When the skb header is cloned, skb_header_unclone() can call pskb_expand_head(), which may move the skb head. The pskb_expand_head() contract requires pointers into the skb header to be reloaded after the call. If the later skb_realloc_headroom() branch is not taken, SIT uses the stale iph6 pointer to read the inner hop limit and DS field. That can read from a freed skb head after the old head's remaining clone is released. Reload iph6 after the offload helper succeeds and before subsequent reads from the inner IPv6 header. Keep the existing reload after skb_realloc_headroom(), since that branch can also replace the skb.

CriticalCVSS 9.8 · v3.1—No exploit Fix available

Published: Jun 25, 2026
Updated: Oct 19, 2026
EPSS: 0.5% · 47th percentile
CWE: CWE-416

Report tools

JSON

Action score

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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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel6.19 and later · before 7.0.13
linux linux kernel3.18 and later · before 5.10.259
linux linux kernel5.11 and later · before 5.15.210
linux linux kernel5.16 and later · before 6.1.176
linux linux kernel6.2 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 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
- 3.18affected
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before fddd41445a0537b093e6b3f6232c9933cad1e48baffected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before 1132e5edc2866c3530be17622153a597095f0e43affected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before 9c67b44edb3598d234efae6e44649eb993c03da5affected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before 0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0affected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before 59f80c919713250fe5d25a4d9aea4e49580fa1d4affected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before 2fa49b2715e1bad12ce3b0fa64e234d9582c8193affected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before cb658c2f5f7977c2a1c77c9f239f4bc8196edb5caffected · git
- 14909664e4e192f4c6f6fcdccd9919af7cf783ab and later · before f0e42f0c4337b1f220de1ddd63f47197c7dee4deaffected · git
- before 3.18not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	bpftool	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-abi-stablelists	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-core	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-cross-headers	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-debug	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-debug-core	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-debug-devel	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-debug-modules	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-debug-modules-extra	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-devel	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-doc	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-headers	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-modules	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-modules-extra	before 4.18.0-553.164.1.el8_10	4.18.0-553.164.1.el8_10
AlmaLinux:8	kernel-rt	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-core	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-debug	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-debug-core	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-debug-devel	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-debug-modules	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-debug-modules-extra	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-devel	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10
AlmaLinux:8	kernel-rt-modules	before 4.18.0-553.164.1.rt7.505.el8_10	4.18.0-553.164.1.rt7.505.el8_10

+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
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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
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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-2026-53226Jun 25, 2026 · gpio: rockchip: fix generic IRQ chip leak on remove
22Monitor
← EarlierCVE-2026-53227Jun 25, 2026 · net: openvswitch: fix possible kfree_skb of ERR_PTR
22Monitor
Later →CVE-2026-53229Jun 25, 2026 · net/mlx5e: xsk: Fix DMA and xdp_frame leak on XDP_TX xmit failure
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 / package	Fixed version	Source
Linux Linux	0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0	Vendor (CNA)
Linux Linux	1132e5edc2866c3530be17622153a597095f0e43	Vendor (CNA)
Linux Linux	2fa49b2715e1bad12ce3b0fa64e234d9582c8193	Vendor (CNA)
Linux Linux	59f80c919713250fe5d25a4d9aea4e49580fa1d4	Vendor (CNA)
Linux Linux	9c67b44edb3598d234efae6e44649eb993c03da5	Vendor (CNA)
Linux Linux	cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c	Vendor (CNA)
Linux Linux	f0e42f0c4337b1f220de1ddd63f47197c7dee4de	Vendor (CNA)
Linux Linux	fddd41445a0537b093e6b3f6232c9933cad1e48b	Vendor (CNA)
azl3 kernel 6.6.141.1-1 on Azure Linux 3.0	6.6.143.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
almalinux:bpftool	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-abi-stablelists	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-core	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-cross-headers	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-debug	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-debug-core	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-debug-devel	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-debug-modules	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-debug-modules-extra	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-devel	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
almalinux:kernel-doc	4.18.0-553.164.1.el8_10 · AlmaLinux:8	Package registry (OSV)
debian:linux	6.1.176-1 · Debian:12	Package registry (OSV)
red hat:kernel-64k-debug-debuginfo	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-64k-debug-devel	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-64k-debug-devel-matched	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-64k-debuginfo	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-64k-devel	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-64k-devel-matched	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-debug-debuginfo	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:kernel-debug-devel	0:6.12.0-211.52.1.el10_2 · Red Hat:enterprise_linux:10.2	Package 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

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-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

SSVC exploitation— → noneOct 16, 2026, 5:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

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

References

git.kernel.org/stable/c/0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0

Show all references (8 more)

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

All records