net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback
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.
- Published
- May 1, 2026
- Updated
- Sep 8, 2026
- EPSS
- 0.7% · 52th percentile
- CWE
- —
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| 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 recordsOther highest-scoring records for the same primary product.
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
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.
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 researchersFinders, 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)
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✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/2094a7cf91b71367b649f991aacc7b579f793d0b
- git.kernel.org/stable/c/33670f780e0120c3dacda188c512bbffe0b6044c
- git.kernel.org/stable/c/732fdeb2987c94b439d51f5cb9addddc2fc48c42
- git.kernel.org/stable/c/a98b78116a27e2a57b696b569b2cb431c95cf9b6
- git.kernel.org/stable/c/c4336a07eb6b2526dc2b62928b5104b41a7f81f5
- git.kernel.org/stable/c/ed71cf465c75f5688b07a35d373cd1d6b589c8ea
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-082556.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.