CVE-2026-23204: net/sched: cls_u32: use skb_header_pointer_careful()
Noroxi assessment
Priority: Monitor (action score 28/100)
- 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: 0.15% (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 13336a6239b9d7c6e61483017bb8bdfe3ceb10a5, 29681ed51e737be14d18ecd1c304c57002e4b72c, 66e4b63d61c15de6ca5332d9ca6db59a404d7136; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.
Low priority for now. Upgrade to Linux Linux 13336a6239b9d7c6e61483017bb8bdfe3ceb10a5, 29681ed51e737be14d18ecd1c304c57002e4b72c, 66e4b63d61c15de6ca5332d9ca6db59a404d7136; 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: net/sched: cls_u32: use skb_header_pointer_careful() skb_header_pointer() does not fully validate negative @offset values. Use skb_header_pointer_careful() instead. GangMin Kim provided a report and a repro fooling u32_classify(): BUG: KASAN: slab-out-of-bounds in u32_classify+0x1180/0x11b0 net/sched/cls_u32.c:221
- BDU:2026-12294
- ALSA-2026:19568
- ALSA-2026:6036
- ALSA-2026:6037
- ALSA-2026:6153
- ALSA-2026:6632
- openSUSE-SU-2026:20572-1
- RHSA-2026:10108
- RHSA-2026:10756
- RHSA-2026:19568
- RHSA-2026:6036
- RHSA-2026:6037
- RHSA-2026:6153
- RHSA-2026:6632
- RHSA-2026:8342
- RHSA-2026:9112
- RHSA-2026:9512
- RHSA-2026:9513
- RHSA-2026:9514
- RHSA-2026:9515
- Published
- Feb 14, 2026
- Updated
- Nov 10, 2026
- EPSS
- 0.1% · 4th percentile
- CWE
- CWE-125
Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 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.
CNA vs NVD score
- NVD
- 7.1
- CNA · Linux
- 7.1
- agree
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.
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 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel2.6.35.1 and later · before 6.6.124
- linux linux kernel6.7 and later · before 6.12.70
- linux linux kernel6.13 and later · before 6.18.10
- linux linux kernel2.6.35
- linux linux kernel6.19
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
- 2.6.35affected
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before 66e4b63d61c15de6ca5332d9ca6db59a404d7136affected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before 29681ed51e737be14d18ecd1c304c57002e4b72caffected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before cfa745830e45ecb75c061aa34330ee0cac941cc7affected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before 13336a6239b9d7c6e61483017bb8bdfe3ceb10a5affected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before e41a23e61259f5526af875c3b86b3d42a9bae0e5affected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before 8a672f177ebe19c93d795fbe967846084fbc7943affected · git
- fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d and later · before cabd1a976375780dabab888784e356f574bbaed8affected · git
- before 2.6.35not affected · semver
- 5.10.260 and later · up to and including 5.10.*not 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:10 | kernel-abi-stablelists | before 6.12.0-124.49.1.el10_1 | 6.12.0-124.49.1.el10_1 |
| AlmaLinux:10 | kernel-doc | before 6.12.0-124.49.1.el10_1 | 6.12.0-124.49.1.el10_1 |
| AlmaLinux:8 | bpftool | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-abi-stablelists | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-core | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-cross-headers | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-debug | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-debug-core | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-debug-devel | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules-extra | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-devel | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-doc | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-headers | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-modules | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-modules-extra | before 4.18.0-553.115.1.el8_10 | 4.18.0-553.115.1.el8_10 |
| AlmaLinux:8 | kernel-rt | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-core | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-debug | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-core | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-devel | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | before 4.18.0-553.115.1.rt7.456.el8_10 | 4.18.0-553.115.1.rt7.456.el8_10 |
+96
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-2026-23200Feb 14, 2026 · ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF22Monitor
- ← EarlierCVE-2026-23202Feb 14, 2026 · spi: tegra210-quad: Protect curr_xfer in tegra_qspi_combined_seq_xfer22Monitor
- Later →CVE-2026-23206Feb 14, 2026 · dpaa2-switch: prevent ZERO_SIZE_PTR dereference when num_ifs is zero22Monitor
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 | 13336a6239b9d7c6e61483017bb8bdfe3ceb10a5 | Vendor (CNA) |
| Linux Linux | 29681ed51e737be14d18ecd1c304c57002e4b72c | Vendor (CNA) |
| Linux Linux | 66e4b63d61c15de6ca5332d9ca6db59a404d7136 | Vendor (CNA) |
| Linux Linux | 8a672f177ebe19c93d795fbe967846084fbc7943 | Vendor (CNA) |
| Linux Linux | cabd1a976375780dabab888784e356f574bbaed8 | Vendor (CNA) |
| Linux Linux | cfa745830e45ecb75c061aa34330ee0cac941cc7 | Vendor (CNA) |
| Linux Linux | e41a23e61259f5526af875c3b86b3d42a9bae0e5 | Vendor (CNA) |
| cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 | Release Notes | Microsoft (MSRC) |
| almalinux:kernel | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-core | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-core | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel-matched | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-core | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-extra | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-devel | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-devel-matched | 5.14.0-687.10.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| debian:linux | 6.1.170-1 · Debian:12 | Package registry (OSV) |
| opensuse:dtb-aarch64 | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-64kb | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-azure | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-default-base | 6.12.0-160000.27.1.160000.2.8 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-docs | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-kvmsmall | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-build | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:kernel-obs-qa | 6.12.0-160000.28.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
+29
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
- high · data can be read
- 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
- High
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.
Attack patterns (CAPEC)
ATT&CK techniques
—
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/29681ed51e737be14d18ecd1c304c57002e4b72c
- git.kernel.org/stable/c/66e4b63d61c15de6ca5332d9ca6db59a404d7136
- git.kernel.org/stable/c/8a672f177ebe19c93d795fbe967846084fbc7943
- git.kernel.org/stable/c/cabd1a976375780dabab888784e356f574bbaed8
- git.kernel.org/stable/c/cfa745830e45ecb75c061aa34330ee0cac941cc7
- git.kernel.org/stable/c/e41a23e61259f5526af875c3b86b3d42a9bae0e5
- 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
- cert-portal.siemens.com/productcert/html/ssa-784472.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.