CVE-2025-21806

mediumpriority · track · 22EPSS 0.002 · 13 %ileDEEUFRRUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.23% (13th) EPSS
CVSS 5.5 · medium
Is it mine?
55 products
Check your exposure
Who says so?
7 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

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).

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

No vendor fix yet; a mitigation is available.

  • MitigationSIMATIC S7-1500 TM MFP - GNU/Linux subsystemsiemens_psirt

    Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.

  • MitigationSIMATIC S7-1500 TM MFP - GNU/Linux subsystemcisa_csaf_ot

    Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.

  • WorkaroundSIMATIC S7-1500 TM MFP - BIOSsiemens_psirt

    Only build and run applications from trusted sources

  • WorkaroundSIMATIC S7-1500 TM MFP - BIOScisa_csaf_ot

    Only build and run applications from trusted sources

  • No fix availableSIMATIC S7-1500 TM MFP - GNU/Linux subsystemsiemens_psirt

    Currently no fix is available

  • No fix availableSIMATIC S7-1500 TM MFP - BIOSsiemens_psirt

    Currently no fix is available

  • No fix availableSIMATIC S7-1500 TM MFP - GNU/Linux subsystemcisa_csaf_ot

    Currently no fix is available

  • No fix availableSIMATIC S7-1500 TM MFP - BIOScisa_csaf_ot

    Currently no fix is available

02

cvss

Technical severity, 0–10. One row per scoring source.

5.5
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 3.6
v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · CISA US
v3.15.5mediumAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · Siemens ProductCERT DE
v3.15.1mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USCWE-20USCWE-20US
04

affected products (55)

Products and version ranges known to be affected.

showing 20 of 55
05

advisories (9)

Vendor and ecosystem advisories describing this.

  • SSA-265688SSA-265688: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.12024-04-09csaf · siemens_psirtDE

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.1. Siemens has released a new version for SIMATIC S7-1500 TM MFP - GNU/Linux subsystem and recommends to update to the latest version. Siemens is preparing further fixes and recommends specific mitigations for products where fixes are not or not yet available. SIMATIC S7-1500 TM MFP V1.1 is no longer maintained and there won't be any update to the CVE list anymore. Please update to the latest version. Note: This SSA advises vulnerabilities for firmware version V1.1 only; for version V1.1.1 refer to SSA-784472.

  • SSA-503939SSA-503939: Vulnerabilities in the BIOS of the SIMATIC S7-1500 TM MFP2025-03-11csaf · siemens_psirtDE

    Multiple vulnerabilities have been identified in the BIOS of the SIMATIC S7-1500 TM MFP. Siemens is preparing fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

  • SSA-784472SSA-784472: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.1.12026-10-13csaf · siemens_psirtDE

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.1.1. Siemens is preparing fixes and recommends specific mitigations for products where fixes are not or not yet available.

  • WID-SEC-W-2025-0461Linux Kernel: Mehrere SchwachstellenDeutsch2025-02-27csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen und um nicht näher spezifizierte Auswirkungen zu erzielen.

  • WID-SEC-W-2026-2253IBM Security Verify Access: Mehrere SchwachstellenDeutsch2026-07-08csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in IBM Security Verify Access ausnutzen, um erweiterte Berechtigungen zu erlangen, beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, sensible Informationen offenzulegen und andere, nicht näher bezeichnete Angriffe durchzuführen.

  • ICSA-24-102-01Siemens SIMATIC S7-1500 TM MFP2024-04-09icsa · cisa_csaf_otUS

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.1. Siemens is preparing fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

  • ICSA-25-072-03Siemens SIMATIC S7-1500 TM MFP2025-03-11icsa · cisa_csaf_otUS

    Multiple vulnerabilities have been identified in the BIOS of the SIMATIC S7-1500 TM MFP. Siemens is preparing fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

  • ICSA-26-295-16Siemens SIMATIC S7-1500 TM MFP2026-10-13icsa · cisa_csaf_otUS

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP V1.1.1. Siemens is preparing fixes and recommends specific mitigations for products where fixes are not or not yet available.

  • CERTFR-2026-AVI-1298Multiples vulnérabilités dans les produits SiemensFrançais2026-10-13vendor · certfrFR
06

also known as (4)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducert_bundcisa_csaf_otsiemens_psirtcertfrNVDCVE.orgMITRE
published 2025-02-27modified 2026-10-15
08

references (28)

External citations — patches, advisories, analysis.

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