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TI-2026-74208 Aliases CVE-2026-101980

Integer underflow in Juniper Junos OS lets attackers crash the kernel

Priority MEDIUM 46CWE-191Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.

Summary

Juniper Networks Junos OS releases before the fixed versions listed below are affected when Extended Echo is configured. The flaw is an integer underflow (CWE-191) in the kernel. An unauthenticated, network-based attacker can send malformed Extended Echo requests that crash the kernel and reboot the Routing Engine, causing a denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

An Integer Underflow vulnerability in the kernel of Juniper Networks Junos OS with Extended Echo configured allows an unauthenticated, network-based attacker to cause a denial of service by a kernel crash.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00471 40th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5 +4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OSbefore 23.2R2-S7.7; 23.4 to before 23.4R2-S8.13; 24.2 to before 24.2R2-S5.5; 24.4 to before 24.4R2-S5; 25.2 to before 25.2R2-S2; 25.4 to before 25.4R1-S3; 26.2 to before 26.2R1-S223.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, 26.2R1-S2Patch availableCNA
  • Junos OS VendorJuniper Affected before 23.2R2-S7.7; 23.4 to before 23.4R2-S8.13; 24.2 to before 24.2R2-S5.5; 24.4 to before 24.4R2-S5; 25.2 to before 25.2R2-S2; 25.4 to before 25.4R1-S3; 26.2 to before 26.2R1-S2 Fixed in 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, 26.2R1-S2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*——Juniper
  • cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* Versions — — ·Juniper

Remediation

Upgrade Junos OS to 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3 or 26.2R1-S2, depending on the release line in use.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, 26.2R1-S2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Juniper Networks Junos OS — supportportal.juniper.net/JSA112188

    11 records Highest priority Priority MEDIUM 8 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2026-74194 Improper authentication in Junos OS J-Web allows root command executionPriority MEDIUM 49
    • TI-2026-74283 Reachable assertion in Junos OS TWAMP client disrupts rmopd servicePriority MEDIUM 46
    • TI-2026-74270 Buffer overflow in Junos OS DHCP process causes denial of servicePriority MEDIUM 44
    Show all 11 records → Advisory →

Timeline

  1. 2026-10-15 Threatist record created from CVE-2026-101980

References

Advisory 1

  • TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-06436 Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r13 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-20885 Apache Commons Text prior to 1.10.0 allows RCE when applied to untrusted input due to insecure interpolation defaults CVSS 3.1CRITICAL 9.8
  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
See all 1284 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences