Linux Kernel: NULL Pointer Dereference (CVE-2025-21682)
Published Last modified Sources: Siemens ProductCERT, Debian, Debian LTS, SUSE, BSI, EUVD, CVE.org, Msrc Update Guide
What is affected, what to do
In the Linux kernel, the following vulnerability has been resolved: eth: bnxt: always recalculate features after XDP clearing, fix null-deref Recalculate features when XDP is detached. Before: # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp # ip li set dev eth0 xdp off # ethtool -k eth0 | grep gro rx-gro-hw: off [requested on] After: # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp # ip li set dev eth0 xdp off # ethtool -k eth0 | grep gro rx-gro-hw: on The fact that HW-GRO doesn't get re-enabled automatically is just a minor annoyance.
Update Linux Kernel to version 6.1.167, Linux Kernel to version 6.6.130, Linux Kernel to version 6.12.11.
- Affected
- Linux Kernel
lt 4.16..6.1.167 - Linux Kernel
lt 6.2..6.6.130 - Linux Kernel
lt 6.7..6.12.11
- Linux Kernel
- Fixed in
- Linux Kernel
6.1.167 - Linux Kernel
6.6.130 - Linux Kernel
6.12.11 - Linux Kernel
6.13
- Linux Kernel
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Metrics
7.3
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
7.3
CVSS v3
Severity High on the scale from 0 to 10.
Source: Siemens ProductCERT, Debian, Debian LTS, SUSE, BSI, EUVD, CVE.org, Msrc Update Guide
0.2 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 14.3
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 45.77 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.3 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.3
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.2 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 14.3
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · not automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 1 October 2025
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-476
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
In the Linux kernel, the following vulnerability has been resolved: eth: bnxt: always recalculate features after XDP clearing, fix null-deref Recalculate features when XDP is detached. Before: # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp # ip li set dev eth0 xdp off # ethtool -k eth0 | grep gro rx-gro-hw: off [requested on] After: # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp # ip li set dev eth0 xdp off # ethtool -k eth0 | grep gro rx-gro-hw: on The fact that HW-GRO doesn't get re-enabled automatically is just a minor annoyance. The real issue is that the features will randomly come back during another reconfiguration which just happens to invoke netdev_update_features(). The driver doesn't handle reconfiguring two things at a time very robustly. Starting with commit 98ba1d931f61 ("bnxt_en: Fix RSS logic in __bnxt_reserve_rings()") we only reconfigure the RSS hash table if the "effective" number of Rx rings has changed. If HW-GRO is enabled "effective" number of rings is 2x what user sees. So if we are in the bad state, with HW-GRO re-enablement "pending" after XDP off, and we lower the rings by / 2 - the HW-GRO rings doing 2x and the ethtool -L doing / 2 may cancel each other out, and the: if (old_rx_rings != bp->hw_resc.resv_rx_rings && condition in __bnxt_reserve_rings() will be false. The RSS map won't get updated, and we'll crash with: BUG: kernel NULL pointer dereference, address: 0000000000000168 RIP: 0010:__bnxt_hwrm_vnic_set_rss+0x13a/0x1a0 bnxt_hwrm_vnic_rss_cfg_p5+0x47/0x180 __bnxt_setup_vnic_p5+0x58/0x110 bnxt_init_nic+0xb72/0xf50 __bnxt_open_nic+0x40d/0xab0 bnxt_open_nic+0x2b/0x60 ethtool_set_channels+0x18c/0x1d0 As we try to access a freed ring. The issue is present since XDP support was added, really, but prior to commit 98ba1d931f61 ("bnxt_en: Fix RSS logic in __bnxt_reserve_rings()") it wasn't causing major issues.
Source: siemens_advisory, Debian Security Advisories, Debian LTS Advisories, suse_csaf, BSI WID Portal, BSI CSAF, ENISA EUVD, cvelistv5, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Linux | Linux |
|
|
| Siemens | SIMATIC S7 |
|
|
Vendors and products
Affected operating systems
| Linux | debian | linux | bookworm |
| Linux | debian | linux-6.1 | bullseye |
| Linux | linux | linux_kernel | 6.13 |
| Linux | linux | linux_kernel | — |
Weakness classes (CWE)
CWE-476NULL Pointer Dereference
Base
The product dereferences a pointer that it expects to be valid but is NULL.
Entry at MITRE CWE-476
References & sources
- git.kernel.orgstable/c/076a694a42ae3f0466bc6e4126050eeb7b7d299a
- git.kernel.orgstable/c/90336fc3d6f5e716ac39a9ddbbde453e23a5aa65
- git.kernel.orgstable/c/08831a894d18abfaabb5bbde7c2069a7fb41dd93
- git.kernel.orgstable/c/f0aa6a37a3dbb40b272df5fc6db93c114688adcd
- Siemens ProductCERTproductcert/html/ssa-082556.html
- Siemens ProductCERTproductcert/html/ssa-019113.html
- Siemens ProductCERTproductcert/html/ssa-457936.html
- Siemens ProductCERTproductcert/html/ssa-784472.html
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedLinux
New references:Show 10 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://git.kernel.org/stable/c/076a694a42ae3f0466bc6e4126050eeb7b7d299aReference added —https://git.kernel.org/stable/c/08831a894d18abfaabb5bbde7c2069a7fb41dd93Reference added —https://git.kernel.org/stable/c/90336fc3d6f5e716ac39a9ddbbde453e23a5aa65Reference added —https://git.kernel.org/stable/c/f0aa6a37a3dbb40b272df5fc6db93c114688adcdReference removed https://git.kernel.org/stable/c/076a694a42ae3f0466bc6e4126050eeb7b7d299a—Reference removed https://git.kernel.org/stable/c/08831a894d18abfaabb5bbde7c2069a7fb41dd93—Reference removed https://git.kernel.org/stable/c/90336fc3d6f5e716ac39a9ddbbde453e23a5aa65—Reference removed https://git.kernel.org/stable/c/f0aa6a37a3dbb40b272df5fc6db93c114688adcd—Reference type removed https://git.kernel.org/stable/c/08831a894d18abfaabb5bbde7c2069a7fb41dd93 Types: Patch—Reference type removed https://git.kernel.org/stable/c/f0aa6a37a3dbb40b272df5fc6db93c114688adcd Types: Patch—Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record modifiedSiemens ADP
Show 7 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/21xxx/CVE-2025-21682.json">CVE-2025-21682</a>Reference added —https://cert-portal.siemens.com/productcert/html/ssa-019113.htmlReference added —https://cert-portal.siemens.com/productcert/html/ssa-082556.htmlReference added —https://cert-portal.siemens.com/productcert/html/ssa-457936.htmlReference added —https://cert-portal.siemens.com/productcert/html/ssa-784472.htmlReference removed https://cert-portal.siemens.com/productcert/html/ssa-019113.html—Reference removed https://cert-portal.siemens.com/productcert/html/ssa-082556.html—Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
Record modifiedLinux
CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
Show the original change
Individual changes of this event as published by NVD Type Action Before After CVSS added —AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:HSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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<a href="https://intel.neosec.eu/en/cve/CVE-2025-21682"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-21682.svg?lang=en" alt="CVE-2025-21682 – NEOSEC Intel" height="20"></a>