NVD / CVE Program· CNA Linux

CVE-2026-43057: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback

Noroxi assessment

Priority: Monitor (action score 30/100)

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: 0.43% (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.
Fixed version: Linux Linux 2094a7cf91b71367b649f991aacc7b579f793d0b, 33670f780e0120c3dacda188c512bbffe0b6044c, 6.1.168.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2094a7cf91b71367b649f991aacc7b579f793d0b, 33670f780e0120c3dacda188c512bbffe0b6044c, 6.1.168 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: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers. Packets with extension headers must fall back onto software checksumming. Since TSO depends on checksum offload, those must revert to GSO. The below commit introduces that fallback. It always checks network header length. For tunneled packets, the inner header length must be checked instead. Extend the check accordingly. A special case is tunneled packets without inner IP protocol. Such as RFC 6951 SCTP in UDP. Those are not standard IPv6 followed by transport header either, so also must revert to the software GSO path.

HighCVSS 7.5 · v3.1—No exploit Fix available

Published: May 1, 2026
Updated: Nov 10, 2026
EPSS: 0.4% · 38th percentile
CWE: —

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CNA vs NVD score

NVD: —
CNA · Linux: 7.5; 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

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

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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 kernel6.1.149 and later · before 6.1.168
linux linux kernel6.6.103 and later · before 6.6.134
linux linux kernel6.12.44 and later · before 6.12.81
linux linux kernel6.16.4 and later · before 6.17
linux linux kernelafter 6.17.1 · before 6.18.22
linux linux kernel6.19 and later · before 6.19.12
linux linux kernel6.17
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
- 794ddbb7b63b6828c75967b9bcd43b086716e7a1, 6.17affected
- a0478d7e888028f85fa7785ea838ce0ca09398e2 and later · before 2094a7cf91b71367b649f991aacc7b579f793d0baffected · git
- 2156d9e9f2e483c8c3906c0ea57ea312c1424235 and later · before ed71cf465c75f5688b07a35d373cd1d6b589c8eaaffected · git
- 041e2f945f82fdbd6fff577b79c33469430297aa and later · before 33670f780e0120c3dacda188c512bbffe0b6044caffected · git
- 864e3396976ef41de6cc7bc366276bf4e084fff2 and later · before a98b78116a27e2a57b696b569b2cb431c95cf9b6affected · git
- 864e3396976ef41de6cc7bc366276bf4e084fff2 and later · before 732fdeb2987c94b439d51f5cb9addddc2fc48c42affected · git
- 864e3396976ef41de6cc7bc366276bf4e084fff2 and later · before c4336a07eb6b2526dc2b62928b5104b41a7f81f5affected · git
- 6.1.149 and later · before 6.1.168affected · semver
- 6.6.103 and later · before 6.6.134affected · semver
- 6.12.44 and later · before 6.12.81affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.170-1	6.1.170-1
Debian:13	linux	before 6.12.85-1	6.12.85-1
Debian:14	linux	before 6.19.12-1	6.19.12-1
SUSE:Linux Micro 6.0	kernel-default	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-kvmsmall	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-rt	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-source	before 6.4.0-50.2	6.4.0-50.2
SUSE:Linux Micro 6.0	kernel-source-rt	before 6.4.0-50.2	6.4.0-50.2

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-2026-43055May 1, 2026 · scsi: target: file: Use kzalloc_flex for aio_cmd
30Monitor
← EarlierCVE-2026-43056May 1, 2026 · net: mana: fix use-after-free in add_adev() error path
31Monitor
Later →CVE-2026-43058May 2, 2026 · media: vidtv: fix pass-by-value structs causing MSAN warnings
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 / package	Fixed version	Source
Linux Linux	2094a7cf91b71367b649f991aacc7b579f793d0b	Vendor (CNA)
Linux Linux	33670f780e0120c3dacda188c512bbffe0b6044c	Vendor (CNA)
Linux Linux	6.1.168	Vendor (CNA)
Linux Linux	6.12.81	Vendor (CNA)
Linux Linux	6.17	Vendor (CNA)
Linux Linux	6.6.134	Vendor (CNA)
Linux Linux	732fdeb2987c94b439d51f5cb9addddc2fc48c42	Vendor (CNA)
Linux Linux	a98b78116a27e2a57b696b569b2cb431c95cf9b6	Vendor (CNA)
Linux Linux	c4336a07eb6b2526dc2b62928b5104b41a7f81f5	Vendor (CNA)
Linux Linux	ed71cf465c75f5688b07a35d373cd1d6b589c8ea	Vendor (CNA)
debian:linux	6.1.170-1 · Debian:12	Package registry (OSV)
suse:kernel-default	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-kvmsmall	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-rt	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-source	6.4.0-50.2 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-source-rt	6.4.0-50.2 · SUSE:Linux Micro 6.0	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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0143 · May 4, 2026(Linux Kernel Güvenlik Bildirimi)

All national notices →

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: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

—

CVSS vector

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

Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

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

References

git.kernel.org/stable/c/2094a7cf91b71367b649f991aacc7b579f793d0b

Show all references (8 more)

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

All records