CVE Vulnerabilities

CVE-2026-21911

Incorrect Calculation

Published: Jan 15, 2026 | Modified: Jan 23, 2026
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
root.io logo minimus.io logo echo.ai logo

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.

Weakness

The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

Affected Software

NameVendorStart VersionEnd Version
Junos_os_evolvedJuniper*21.4 (excluding)
Junos_os_evolvedJuniper21.4 (including)21.4 (including)
Junos_os_evolvedJuniper21.4-r1 (including)21.4-r1 (including)
Junos_os_evolvedJuniper21.4-r1-s1 (including)21.4-r1-s1 (including)
Junos_os_evolvedJuniper21.4-r1-s2 (including)21.4-r1-s2 (including)
Junos_os_evolvedJuniper21.4-r2 (including)21.4-r2 (including)
Junos_os_evolvedJuniper21.4-r2-s1 (including)21.4-r2-s1 (including)
Junos_os_evolvedJuniper21.4-r2-s2 (including)21.4-r2-s2 (including)
Junos_os_evolvedJuniper21.4-r3 (including)21.4-r3 (including)
Junos_os_evolvedJuniper21.4-r3-s1 (including)21.4-r3-s1 (including)
Junos_os_evolvedJuniper21.4-r3-s2 (including)21.4-r3-s2 (including)
Junos_os_evolvedJuniper21.4-r3-s3 (including)21.4-r3-s3 (including)
Junos_os_evolvedJuniper21.4-r3-s4 (including)21.4-r3-s4 (including)
Junos_os_evolvedJuniper21.4-r3-s5 (including)21.4-r3-s5 (including)
Junos_os_evolvedJuniper21.4-r3-s6 (including)21.4-r3-s6 (including)
Junos_os_evolvedJuniper22.2 (including)22.2 (including)
Junos_os_evolvedJuniper22.2-r1 (including)22.2-r1 (including)
Junos_os_evolvedJuniper22.2-r1-s1 (including)22.2-r1-s1 (including)
Junos_os_evolvedJuniper22.2-r1-s2 (including)22.2-r1-s2 (including)
Junos_os_evolvedJuniper22.2-r2 (including)22.2-r2 (including)
Junos_os_evolvedJuniper22.2-r2-s1 (including)22.2-r2-s1 (including)
Junos_os_evolvedJuniper22.2-r2-s2 (including)22.2-r2-s2 (including)
Junos_os_evolvedJuniper22.2-r3 (including)22.2-r3 (including)
Junos_os_evolvedJuniper22.2-r3-s1 (including)22.2-r3-s1 (including)
Junos_os_evolvedJuniper22.2-r3-s2 (including)22.2-r3-s2 (including)
Junos_os_evolvedJuniper22.2-r3-s3 (including)22.2-r3-s3 (including)
Junos_os_evolvedJuniper22.3 (including)22.3 (including)
Junos_os_evolvedJuniper22.3-r1 (including)22.3-r1 (including)
Junos_os_evolvedJuniper22.3-r1-s1 (including)22.3-r1-s1 (including)
Junos_os_evolvedJuniper22.3-r1-s2 (including)22.3-r1-s2 (including)
Junos_os_evolvedJuniper22.3-r2 (including)22.3-r2 (including)
Junos_os_evolvedJuniper22.3-r2-s1 (including)22.3-r2-s1 (including)
Junos_os_evolvedJuniper22.3-r2-s2 (including)22.3-r2-s2 (including)
Junos_os_evolvedJuniper22.3-r3 (including)22.3-r3 (including)
Junos_os_evolvedJuniper22.3-r3-s1 (including)22.3-r3-s1 (including)
Junos_os_evolvedJuniper22.3-r3-s2 (including)22.3-r3-s2 (including)
Junos_os_evolvedJuniper22.4 (including)22.4 (including)
Junos_os_evolvedJuniper22.4-r1 (including)22.4-r1 (including)
Junos_os_evolvedJuniper22.4-r1-s1 (including)22.4-r1-s1 (including)
Junos_os_evolvedJuniper22.4-r1-s2 (including)22.4-r1-s2 (including)
Junos_os_evolvedJuniper22.4-r2 (including)22.4-r2 (including)
Junos_os_evolvedJuniper22.4-r2-s1 (including)22.4-r2-s1 (including)
Junos_os_evolvedJuniper22.4-r2-s2 (including)22.4-r2-s2 (including)
Junos_os_evolvedJuniper22.4-r3 (including)22.4-r3 (including)
Junos_os_evolvedJuniper22.4-r3-s1 (including)22.4-r3-s1 (including)
Junos_os_evolvedJuniper23.2 (including)23.2 (including)
Junos_os_evolvedJuniper23.2-r1 (including)23.2-r1 (including)
Junos_os_evolvedJuniper23.2-r1-s1 (including)23.2-r1-s1 (including)
Junos_os_evolvedJuniper23.2-r1-s2 (including)23.2-r1-s2 (including)
Junos_os_evolvedJuniper23.2-r2 (including)23.2-r2 (including)
Junos_os_evolvedJuniper23.4 (including)23.4 (including)
Junos_os_evolvedJuniper23.4-r1 (including)23.4-r1 (including)
Junos_os_evolvedJuniper23.4-r1-s1 (including)23.4-r1-s1 (including)
Junos_os_evolvedJuniper23.4-r2 (including)23.4-r2 (including)

Potential Mitigations

  • Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
  • Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
  • Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
  • Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

References