CVE-2026-23243: RDMA/umad: Reject negative data_len in ib_umad_write
Noroxi assessment
Priority: Monitor (action score 31/100)
- 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: 0.17% (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 1371ef6b1ecf3676b8942f5dfb3634fb0648128e, 205955f29c26330b1dc7fdeadd5bb97c38e26f56, 362e45fd9069ffa1523f9f1633b606ebf72060d7; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1.
Low priority for now. Upgrade to Linux Linux 1371ef6b1ecf3676b8942f5dfb3634fb0648128e, 205955f29c26330b1dc7fdeadd5bb97c38e26f56, 362e45fd9069ffa1523f9f1633b606ebf72060d7; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1 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: RDMA/umad: Reject negative data_len in ib_umad_write ib_umad_write computes data_len from user-controlled count and the MAD header sizes. With a mismatched user MAD header size and RMPP header length, data_len can become negative and reach ib_create_send_mad(). This can make the padding calculation exceed the segment size and trigger an out-of-bounds memset in alloc_send_rmpp_list(). Add an explicit check to reject negative data_len before creating the send buffer. KASAN splat: [ 211.363464] BUG: KASAN: slab-out-of-bounds in ib_create_send_mad+0xa01/0x11b0 [ 211.364077] Write of size 220 at addr ffff88800c3fa1f8 by task spray_thread/102 [ 211.365867] ib_create_send_mad+0xa01/0x11b0 [ 211.365887] ib_umad_write+0x853/0x1c80
- BDU:2026-11665
- ALSA-2026:18587
- ALSA-2026:21706
- ALSA-2026:21745
- RHSA-2026:13936
- RHSA-2026:14137
- RHSA-2026:14339
- RHSA-2026:15883
- RHSA-2026:18587
- RHSA-2026:19521
- RHSA-2026:19875
- RHSA-2026:20593
- RHSA-2026:21209
- RHSA-2026:21706
- RHSA-2026:21745
- RHSA-2026:26535
- RHSA-2026:26570
- RHSA-2026:27729
- RHSA-2026:41236
- RLSA-2026:21706
- Published
- Mar 18, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 7th percentile
- CWE
- CWE-787
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.8
- 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.
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 kernel2.6.24.1 and later · before 5.10.252
- linux linux kernel5.11 and later · before 5.15.202
- linux linux kernel5.16 and later · before 6.1.165
- linux linux kernel6.2 and later · before 6.6.128
- linux linux kernel6.7 and later · before 6.12.75
- linux linux kernel6.13 and later · before 6.18.14
- linux linux kernel6.19 and later · before 6.19.4
- linux linux kernel2.6.24
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
- 2.6.24affected
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 1371ef6b1ecf3676b8942f5dfb3634fb0648128eaffected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 362e45fd9069ffa1523f9f1633b606ebf72060d7affected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 6eb2919474ca105c5b13d19574e25f0ddcf19ca2affected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0daffected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 9c80d688f402539dfc8f336de1380d6b4ee14316affected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 205955f29c26330b1dc7fdeadd5bb97c38e26f56affected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34baffected · git
- 2be8e3ee8efd6f99ce454115c29d09750915021a and later · before 5551b02fdbfd85a325bb857f3a8f9c9f33397ed2affected · git
- before 2.6.24not 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:8 | bpftool | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-abi-stablelists | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-core | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-cross-headers | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-debug | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-debug-core | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-debug-devel | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules-extra | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-devel | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-doc | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-headers | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-modules | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-modules-extra | before 4.18.0-553.126.1.el8_10 | 4.18.0-553.126.1.el8_10 |
| AlmaLinux:8 | kernel-rt | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-core | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-debug | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-core | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-devel | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-devel | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.el8_10 |
| AlmaLinux:8 | kernel-rt-modules | before 4.18.0-553.126.1.rt7.467.el8_10 | 4.18.0-553.126.1.rt7.467.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-2025-71267Mar 18, 2026 · fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST22Monitor
- ← EarlierCVE-2026-23242Mar 18, 2026 · RDMA/siw: Fix potential NULL pointer dereference in header processing30Monitor
- Later →CVE-2026-23245Mar 18, 2026 · net/sched: act_gate: snapshot parameters with RCU on replace31Monitor
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 | 1371ef6b1ecf3676b8942f5dfb3634fb0648128e | Vendor (CNA) |
| Linux Linux | 205955f29c26330b1dc7fdeadd5bb97c38e26f56 | Vendor (CNA) |
| Linux Linux | 362e45fd9069ffa1523f9f1633b606ebf72060d7 | Vendor (CNA) |
| Linux Linux | 52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b | Vendor (CNA) |
| Linux Linux | 5551b02fdbfd85a325bb857f3a8f9c9f33397ed2 | Vendor (CNA) |
| Linux Linux | 6eb2919474ca105c5b13d19574e25f0ddcf19ca2 | Vendor (CNA) |
| Linux Linux | 9c80d688f402539dfc8f336de1380d6b4ee14316 | Vendor (CNA) |
| Linux Linux | a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d | Vendor (CNA) |
| azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 | 6.6.130.1-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| almalinux:kernel | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-core | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-core | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel-matched | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-core | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-extra | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-devel | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:kernel-64k-devel-matched | 5.14.0-687.5.1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| debian:linux | 6.1.170-1 · Debian:12 | Package registry (OSV) |
| red hat:bpftool-debuginfo | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debug-debuginfo | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debug-devel | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debug-devel-matched | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debuginfo | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debuginfo-common-aarch64 | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debuginfo-common-ppc64le | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
| red hat:kernel-debuginfo-common-s390x | 0:5.14.0-70.178.1.el9_0 · Red Hat:rhel_e4s:9.0::appstream | Package registry (OSV) |
+18
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).
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
- high · data or configuration can be modified
- 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
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Show all references (10 more)Show less
- git.kernel.org/stable/c/205955f29c26330b1dc7fdeadd5bb97c38e26f56
- git.kernel.org/stable/c/362e45fd9069ffa1523f9f1633b606ebf72060d7
- git.kernel.org/stable/c/52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b
- git.kernel.org/stable/c/5551b02fdbfd85a325bb857f3a8f9c9f33397ed2
- git.kernel.org/stable/c/6eb2919474ca105c5b13d19574e25f0ddcf19ca2
- git.kernel.org/stable/c/9c80d688f402539dfc8f336de1380d6b4ee14316
- git.kernel.org/stable/c/a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d
- 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.