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NVD / CVE Program· CNA Linux

CVE-2025-21806: net: let net.core.dev_weight always be non-zero

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: 0.22% (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 0e2f1d93d287d544d26f8ff293ea820a8079b9f8, 1489824e5226a26841c70639ebd2d1aed390764b, 33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada.

Low priority for now. Upgrade to Linux Linux 0e2f1d93d287d544d26f8ff293ea820a8079b9f8, 1489824e5226a26841c70639ebd2d1aed390764b, 33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada 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: let net.core.dev_weight always be non-zero The following problem was encountered during stability test: (NULL net_device): NAPI poll function process_backlog+0x0/0x530 \ returned 1, exceeding its budget of 0. ------------[ cut here ]------------ list_add double add: new=ffff88905f746f48, prev=ffff88905f746f48, \ next=ffff88905f746e40. WARNING: CPU: 18 PID: 5462 at lib/list_debug.c:35 \ __list_add_valid_or_report+0xf3/0x130 CPU: 18 UID: 0 PID: 5462 Comm: ping Kdump: loaded Not tainted 6.13.0-rc7+ RIP: 0010:__list_add_valid_or_report+0xf3/0x130 Call Trace: ? __warn+0xcd/0x250 ? __list_add_valid_or_report+0xf3/0x130 enqueue_to_backlog+0x923/0x1070 netif_rx_internal+0x92/0x2b0 __netif_rx+0x15/0x170 loopback_xmit+0x2ef/0x450 dev_hard_start_xmit+0x103/0x490 __dev_queue_xmit+0xeac/0x1950 ip_finish_output2+0x6cc/0x1620 ip_output+0x161/0x270 ip_push_pending_frames+0x155/0x1a0 raw_sendmsg+0xe13/0x1550 __sys_sendto+0x3bf/0x4e0 __x64_sys_sendto+0xdc/0x1b0 do_syscall_64+0x5b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e The reproduction command is as follows: sysctl -w net.core.dev_weight=0 ping 127.0.0.1 This is because when the napi's weight is set to 0, process_backlog() may return 0 and clear the NAPI_STATE_SCHED bit of napi->state, causing this napi to be re-polled in net_rx_action() until __do_softirq() times out. Since the NAPI_STATE_SCHED bit has been cleared, napi_schedule_rps() can be retriggered in enqueue_to_backlog(), causing this issue. Making the napi's weight always non-zero solves this problem. Triggering this issue requires system-wide admin (setting is not namespaced).

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 27, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 13th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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  • No public exploit code on record
  • A fix has been released

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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.

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Affected 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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.13 and later · before 5.4.291
  • linux linux kernel5.5 and later · before 5.10.235
  • linux linux kernel5.11 and later · before 5.15.179
  • linux linux kernel5.16 and later · before 6.1.129
  • linux linux kernel6.2 and later · before 6.6.76
  • linux linux kernel6.7 and later · before 6.12.13
  • linux linux kernel6.13 and later · before 6.13.2
  • linux linux kernel2.6.12

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
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before d0e0f9c8218826926d7692980c98236d9f21fd3caffected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before c337c08819a4ec49edfdcd8fc46fbee120d8a5b2affected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before 0e2f1d93d287d544d26f8ff293ea820a8079b9f8affected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before 5860abbf15eeb61838b5e32e721ba67b0aa84450affected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before 6ce38b5a6a49e65bad163162a54cb3f104c40b48affected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before 33e2168788f8fb5cb8bd4f36cb1ef37d1d34dadaaffected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before 1489824e5226a26841c70639ebd2d1aed390764baffected · git
    • e3876605450979fe52a1a03e7eb78a89bf59e76a and later · before d1f9f79fa2af8e3b45cffdeef66e05833480148aaffected · git
    • before 2.6.12not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.129-16.1.129-1
Debian:13linuxbefore 6.12.13-16.12.13-1
SUSE:Linux Micro 6.0kernel-livepatch-MICRO-6-0-RT_Update_7before 1-1.31-1.3
SUSE:Linux Micro 6.0kernel-rtbefore 6.4.0-30.16.4.0-30.1
SUSE:Linux Micro 6.0kernel-source-rtbefore 6.4.0-30.16.4.0-30.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • 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 KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-21801Feb 27, 2025 · net: ravb: Fix missing rtnl lock in suspend/resume path
    22Monitor
  • ← EarlierCVE-2025-21802Feb 27, 2025 · net: hns3: fix oops when unload drivers paralleling
    22Monitor
  • Later →CVE-2025-21808Feb 27, 2025 · net: xdp: Disallow attaching device-bound programs in generic mode
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0e2f1d93d287d544d26f8ff293ea820a8079b9f8Vendor (CNA)
Linux Linux1489824e5226a26841c70639ebd2d1aed390764bVendor (CNA)
Linux Linux33e2168788f8fb5cb8bd4f36cb1ef37d1d34dadaVendor (CNA)
Linux Linux5860abbf15eeb61838b5e32e721ba67b0aa84450Vendor (CNA)
Linux Linux6ce38b5a6a49e65bad163162a54cb3f104c40b48Vendor (CNA)
Linux Linuxc337c08819a4ec49edfdcd8fc46fbee120d8a5b2Vendor (CNA)
Linux Linuxd0e0f9c8218826926d7692980c98236d9f21fd3cVendor (CNA)
Linux Linuxd1f9f79fa2af8e3b45cffdeef66e05833480148aVendor (CNA)
debian:linux6.1.129-1 · Debian:12Package registry (OSV)
suse:kernel-livepatch-MICRO-6-0-RT_Update_71-1.3 · SUSE:Linux Micro 6.0Package registry (OSV)
suse:kernel-rt6.4.0-30.1 · SUSE:Linux Micro 6.0Package registry (OSV)
suse:kernel-source-rt6.4.0-30.1 · SUSE:Linux Micro 6.0Package 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.

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 researchers

Finders, 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

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (12 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records