CVE-2026-31495: netfilter: ctnetlink: use netlink policy range checks
Noroxi assessment
Priority: Monitor (action score 22/100)
- 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 2ef71307c86a9f866d6e28f1a0c06e2e9d794474, 435b576cd2faa75154777868f8cbb73bf71644d3, 45c33e79ae705b7af97e3117672b6cd258dd0b1b; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.
Low priority for now. Upgrade to Linux Linux 2ef71307c86a9f866d6e28f1a0c06e2e9d794474, 435b576cd2faa75154777868f8cbb73bf71644d3, 45c33e79ae705b7af97e3117672b6cd258dd0b1b; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes 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: ctnetlink: use netlink policy range checks Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors. - CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check. - CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count. - CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks. - CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags. Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.
- Published
- Apr 22, 2026
- Updated
- Oct 15, 2026
- EPSS
- 0.1% · 2th percentile
- CWE
- —
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
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.
We use this product, ask for helpAffected 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 kernel2.6.22.1 and later · before 5.10.253
- linux linux kernel5.11 and later · before 5.15.203
- linux linux kernel5.16 and later · before 6.1.168
- linux linux kernel6.2 and later · before 6.6.131
- linux linux kernel6.7 and later · before 6.12.80
- linux linux kernel6.13 and later · before 6.18.21
- linux linux kernel6.19 and later · before 6.19.11
- linux linux kernel2.6.22
- 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
- 2.6.22affected
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 435b576cd2faa75154777868f8cbb73bf71644d3affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 2ef71307c86a9f866d6e28f1a0c06e2e9d794474affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 4f7d25f3f0786402ba48ff7d13b6241d77d975f5affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before fcec5ce2d73a41668b24e3f18c803541602a59f6affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 675c913b940488a84effdeeac5a1cfb657b59804affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before c6cb41eaae875501eaaa487b8db6539feb092292affected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 45c33e79ae705b7af97e3117672b6cd258dd0b1baffected · git
- c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 and later · before 8f15b5071b4548b0aafc03b366eb45c9c6566704affected · git
- before 2.6.22not affected · 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 6.19.11-1 | 6.19.11-1 |
| openSUSE:Leap 16.0 | dtb-aarch64 | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-64kb | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-azure | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-default | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-default-base | before 6.12.0-160000.36.1.160000.2.17 | 6.12.0-160000.36.1.160000.2.17 |
| openSUSE:Leap 16.0 | kernel-docs | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-rt | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-source | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-syms | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | before 6.12.0-160000.36.1 | 6.12.0-160000.36.1 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_17 | before 1-150700.15.3.1 | 1-150700.15.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_17 | before 1-150700.1.3.1 | 1-150700.1.3.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-64kb | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-default | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-default-base | before 6.4.0-150700.53.63.1.150700.17.37.1 | 6.4.0-150700.53.63.1.150700.17.37.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-source | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-zfcpdump | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | kernel-docs | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
+22
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- 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
Published before and after this one in the same product
- ← EarlierCVE-2026-31493Apr 22, 2026 · RDMA/efa: Fix use of completion ctx after free31Monitor
- ← EarlierCVE-2026-31494Apr 22, 2026 · net: macb: use the current queue number for stats31Monitor
- Later →CVE-2026-31496Apr 22, 2026 · netfilter: nf_conntrack_expect: skip expectations in other netns via proc22Monitor
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 | 2ef71307c86a9f866d6e28f1a0c06e2e9d794474 | Vendor (CNA) |
| Linux Linux | 435b576cd2faa75154777868f8cbb73bf71644d3 | Vendor (CNA) |
| Linux Linux | 45c33e79ae705b7af97e3117672b6cd258dd0b1b | Vendor (CNA) |
| Linux Linux | 4f7d25f3f0786402ba48ff7d13b6241d77d975f5 | Vendor (CNA) |
| Linux Linux | 675c913b940488a84effdeeac5a1cfb657b59804 | Vendor (CNA) |
| Linux Linux | 8f15b5071b4548b0aafc03b366eb45c9c6566704 | Vendor (CNA) |
| Linux Linux | c6cb41eaae875501eaaa487b8db6539feb092292 | Vendor (CNA) |
| Linux Linux | fcec5ce2d73a41668b24e3f18c803541602a59f6 | Vendor (CNA) |
| azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 | 6.6.134.1-2 · CBL-Mariner Releases | Microsoft (MSRC) |
| cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 | Release Notes | Microsoft (MSRC) |
| debian:linux | 6.1.170-1 · Debian:12 | Package registry (OSV) |
| opensuse:dtb-aarch64 | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-64kb | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-azure | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default-base | 6.12.0-160000.36.1.160000.2.17 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-docs | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-kvmsmall | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-build | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-qa | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-rt | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-source | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-syms | 6.12.0-160000.36.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| suse:kernel-64kb | 6.12.0-160000.36.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
| suse:kernel-azure | 6.12.0-160000.36.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-default | 6.4.0-48.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-default-base | 6.4.0-48.1.21.25 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-docs | 6.12.0-160000.36.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
| suse:kernel-kvmsmall | 6.4.0-48.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-obs-build | 6.12.0-160000.36.1 · SUSE:Linux Micro Extras 6.2 | Package registry (OSV) |
+5
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 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).
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
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
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
Show all references (10 more)Show less
- git.kernel.org/stable/c/435b576cd2faa75154777868f8cbb73bf71644d3
- git.kernel.org/stable/c/45c33e79ae705b7af97e3117672b6cd258dd0b1b
- git.kernel.org/stable/c/4f7d25f3f0786402ba48ff7d13b6241d77d975f5
- git.kernel.org/stable/c/675c913b940488a84effdeeac5a1cfb657b59804
- git.kernel.org/stable/c/8f15b5071b4548b0aafc03b366eb45c9c6566704
- git.kernel.org/stable/c/c6cb41eaae875501eaaa487b8db6539feb092292
- git.kernel.org/stable/c/fcec5ce2d73a41668b24e3f18c803541602a59f6
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.