CVE-2026-21911

mediumpriority · track · 0EPSS 0.002 · 15 %ileDEEUNLUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.24% (15th) EPSS
CVSS 6.5 · medium
Is it mine?
19 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · cert_bund · ncsc_nl

EPSS · scored 2026-10-27

An Incorrect Calculation vulnerability in the Layer 2 Control Protocol Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-adjacent attacker flapping the management interface to cause the learning of new MACs over label-switched interfaces (LSI) to stop while generating a flood of logs, resulting in high CPU usage. When the issue is seen, the following log message will be generated: op:1 flag:0x6 mac:xx:xx:xx:xx:xx:xx bd:2 ifl:13302 reason:0(REASON_NONE) i-op:6(INTRNL_OP_HW_FORCE_DELETE) status:10 lstatus:10 err:26(GETIFBD_VALIDATE_FAILED) err-reason 4(IFBD_VALIDATE_FAIL_EPOCH_MISMATCH) hw_wr:0x4 ctxsync:0 fwdsync:0 rtt-id:51 p_ifl:0 fwd_nh:0 svlbnh:0 event:- smask:0x100000000 dmask:0x0 mplsmask 0x1 act:0x5800 extf:0x0 pfe-id 0 hw-notif-ifl 13302 programmed-ifl 4294967295 pseudo-vtep underlay-ifl-idx 0 stack:GET_MAC, ALLOCATE_MAC, GET_IFL, GET_IFF, GET_IFBD, STOP, This issue affects Junos OS Evolved:  * all versions before 21.4R3-S7-EVO,  * from 22.2 before 22.2R3-S4-EVO,  * from 22.3 before 22.3R3-S3-EVO,  * from 22.4 before 22.4R3-S2-EVO,  * from 23.2 before 23.2R2-S1-EVO,  * from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO.

01

cvss

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

7.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.9–7.1

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · sirt@juniper.net USexploitability 2.8 · impact 3.6
v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · NCSC-NL NL
v4.07.1highCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Ambersecondary · ENISA EU
v4.07.1highCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Ambersecondary · sirt@juniper.net US
v4.04.9mediumCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Ambersecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-682USCWE-682US
04

affected products (19)

Products and version ranges known to be affected.

05

advisories (2)

Vendor and ecosystem advisories describing this.

  • NCSC-2026-0017Kwetsbaarheden verholpen in Juniper Networks JunOSNL2026-01-16csaf · ncsc_nlNL

    Juniper heeft kwetsbaarheden verholpen in Junos OS (Specifiek voor SRX en MX Series apparaten).

  • WID-SEC-W-2026-0117Juniper Junos OS, Junos Space: Mehrere SchwachstellenDeutsch2026-01-14csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Juniper JUNOS und Juniper Junos Space ausnutzen, um falsche Informationen darzustellen, beliebigen Code mit Root-Rechten auszuführen, Daten zu manipulieren, vertrauliche Informationen offenzulegen und einen Denial-of-Service-Zustand zu verursachen.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdcert_bundncsc_nlnvdNVDCVE.orgMITRE
published 2026-01-15modified 2026-06-17
08

references (7)

External citations — patches, advisories, analysis.

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