CVE-2026-31664: xfrm: clear trailing padding in build_polexpire()
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 71a98248c63c535eaa4d4c22f099b68d902006d0, a5127501c8d30b5728791b1e340284ca5c9cc4bd, ac6985903db047eaff54db929e4bf6b06782788e; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.
Low priority for now. Upgrade to Linux Linux 71a98248c63c535eaa4d4c22f099b68d902006d0, a5127501c8d30b5728791b1e340284ca5c9cc4bd, ac6985903db047eaff54db929e4bf6b06782788e; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1; 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: xfrm: clear trailing padding in build_polexpire() build_expire() clears the trailing padding bytes of struct xfrm_user_expire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do this for struct xfrm_user_polexpire. The padding bytes after the __u8 hard field are left uninitialized from the heap allocation, and are then sent to userspace via netlink multicast to XFRMNLGRP_EXPIRE listeners, leaking kernel heap memory contents. Add the missing memset_after() call, matching build_expire().
- Published
- Apr 24, 2026
- Updated
- Nov 11, 2026
- EPSS
- 0.1% · 1th percentile
- CWE
- —
Report tools
Action score
22
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
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.
Is your version affected? Check itNoroxi 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 |
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
- 2.6.12affected
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before a5127501c8d30b5728791b1e340284ca5c9cc4bdaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e6f4ffe8596947a595c9544e73a73adcb0568b88affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ac6985903db047eaff54db929e4bf6b06782788eaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before c221ed63a2769a0af8bd849dfe25740048f34ef4affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before eda30846ea54f8ed218468e5480c8305ca645e37affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b1dfd6b27df35ef4f87825aa5f607378d23ff0f2affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e1af65c669ebb1666c54576614c01a7f9ffcfff6affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 71a98248c63c535eaa4d4c22f099b68d902006d0affected · git
- before 2.6.12not affected · semver
Affected versions · NVD (7)
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel2.6.12.1 and later · before 6.1.169
- linux linux kernel6.2 and later · before 6.6.135
- linux linux kernel6.7 and later · before 6.12.82
- linux linux kernel6.13 and later · before 6.18.23
- linux linux kernel6.19 and later · before 6.19.13
- linux linux kernel2.6.12
- linux linux kernel7.0
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 6.19.13-1 | 6.19.13-1 |
| 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 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 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | kernel-obs-build | 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-syms | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP7 | kernel-azure | before 6.4.0-150700.53.63.1 | 6.4.0-150700.53.63.1 |
| SUSE:Linux Micro 6.0 | kernel-default | before 6.4.0-48.1 | 6.4.0-48.1 |
| SUSE:Linux Micro 6.0 | kernel-default-base | before 6.4.0-48.1.21.25 | 6.4.0-48.1.21.25 |
| SUSE:Linux Micro 6.0 | kernel-kvmsmall | before 6.4.0-48.1 | 6.4.0-48.1 |
| SUSE:Linux Micro 6.0 | kernel-source | before 6.4.0-48.1 | 6.4.0-48.1 |
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-2026-31662Apr 24, 2026 · tipc: fix bc_ackers underflow on duplicate GRP_ACK_MSG30Monitor
- ← EarlierCVE-2026-31663Apr 24, 2026 · xfrm: hold dev ref until after transport_finish NF_HOOK31Monitor
- Later →CVE-2026-31665Apr 24, 2026 · netfilter: nft_ct: fix use-after-free in timeout object destroy31Monitor
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 | 71a98248c63c535eaa4d4c22f099b68d902006d0 | Vendor (CNA) |
| Linux Linux | a5127501c8d30b5728791b1e340284ca5c9cc4bd | Vendor (CNA) |
| Linux Linux | ac6985903db047eaff54db929e4bf6b06782788e | Vendor (CNA) |
| Linux Linux | b1dfd6b27df35ef4f87825aa5f607378d23ff0f2 | Vendor (CNA) |
| Linux Linux | c221ed63a2769a0af8bd849dfe25740048f34ef4 | Vendor (CNA) |
| Linux Linux | e1af65c669ebb1666c54576614c01a7f9ffcfff6 | Vendor (CNA) |
| Linux Linux | e6f4ffe8596947a595c9544e73a73adcb0568b88 | Vendor (CNA) |
| Linux Linux | eda30846ea54f8ed218468e5480c8305ca645e37 | Vendor (CNA) |
| azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 | 6.6.137.1-1 · 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) |
| suse:kernel-64kb | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | Package registry (OSV) |
| suse:kernel-azure | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP7 | 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 | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7 | Package registry (OSV) |
| suse:kernel-kvmsmall | 6.4.0-48.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP7_Update_17 | 1-150700.15.3.1 · SUSE:Linux Enterprise Live Patching 15 SP7 | Package registry (OSV) |
| suse:kernel-obs-build | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7 | Package registry (OSV) |
| suse:kernel-source | 6.4.0-48.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-syms | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7 | Package registry (OSV) |
| suse:kernel-zfcpdump | 6.4.0-150700.53.63.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | 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.
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
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 (2)
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (10 more)Show less
- git.kernel.org/stable/c/a5127501c8d30b5728791b1e340284ca5c9cc4bd
- git.kernel.org/stable/c/ac6985903db047eaff54db929e4bf6b06782788e
- git.kernel.org/stable/c/b1dfd6b27df35ef4f87825aa5f607378d23ff0f2
- git.kernel.org/stable/c/c221ed63a2769a0af8bd849dfe25740048f34ef4
- git.kernel.org/stable/c/e1af65c669ebb1666c54576614c01a7f9ffcfff6
- git.kernel.org/stable/c/e6f4ffe8596947a595c9544e73a73adcb0568b88
- git.kernel.org/stable/c/eda30846ea54f8ed218468e5480c8305ca645e37
- 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.