CVE Intelligence
High Memory corruption

CVE-2026-101976 — Junos OS and Junos OS Evolved: In a non-4byte-AS scenario a specific BGP update causes an rpd crash

An Out-of-bounds Write vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an eBGP peer which has not negotiated four-octet-AS capability sending a specifically malformed BGP update to cause a Denial-of-Service (DoS).

Published Oct 14, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: juniper

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+6
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.46%
ahead of 38% of scored CVEs · Oct 15, 2026
Affects
Juniper Networks
Junos OS and 1 more
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Juniper Networks Junos OS, Juniper Networks Junos Os Evolved).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Juniper Networks Junos OS ≥ 23.4 and < 23.4R2-S8.13≥ 24.2 and < 24.2R2-S5.5≥ 24.4 and < 24.4R2-S5≥ 25.2 and < 25.2R2-S2≥ 25.4 and < 25.4R1-S3≥ 26.2 and < 26.2R1-S2< 23.2R2-S7.7 Vulnerable CVE Program (cve.org) e CISA ADP
Juniper Networks Junos Os Evolved ≥ 25.4X300 and < 25.4X300-D40-EVO≥ 25.2X100 and < 25.2X100-D35-EVOversion 23.4X100≥ 26.2 and < 26.2R1-S2-EVO≥ 25.4 and < 25.4R1-S3-EVO≥ 25.2 and < 25.2R2-S2-EVO≥ 24.4 and < 24.4R2-S5-EVO≥ 24.2 and < 24.2R2-S5.6-EVO
and 2 more ≥ 23.4 and < 23.4R2-S8.11-EVO< 23.2R2-S7.7-EVO
Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.7 CVSS 4.0 High — — sirt@juniper.net via NIST National Vulnerability Database
8.7 CVSS 4.0 High — — juniper via CVE Program (cve.org) e CISA ADP
7.5 CVSS 3.1 High 3.9 3.6 sirt@juniper.net via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.1 High — — juniper via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: sirt@juniper.net)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-787 · Out-of-bounds Write

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Awaiting Analysis
    Oct 15, 2026 · NIST National Vulnerability Database
  • Affected products removed · 10
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Affected products added · juniper networks/junos os evolved
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Affected products added · juniper networks/junos os, juniper networks/junos os evolved
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 14, 2026
  • CVSS changed · 7.5
    Oct 14, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 14, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 14, 2026 · Alertas do Telegram
  • CVE published
    Oct 14, 2026 · juniper

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 14, 2026 – Oct 14, 2026
  • 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

3 on the record

Elsewhere on this site

Juniper Networks
every CVE for this vendor
Memory corruption
same class
CWE-787
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-102077 Junos OS: MX Series with SPC3: In a source NAT scenario malformed packets will lead to resource leaks and eventually traffic stops 1d
  • CVE-2026-101983 Junos OS and Junos OS Evolved: An attacker causes remote code execution when J-Web virtual-domain is configured 1d
  • CVE-2026-101982 Junos OS and Junos OS Evolved: A EVPN peer causes an rpd crash or root-level compromise when EVPN-VPWS is used 1d
  • CVE-2026-101972 Junos OS and Junos OS Evolved: Malformed OSPF packets causes routing disruption when OSPF is enabled 1d
  • CVE-2026-101964 Junos OS and Junos OS Evolved: An attacker can cause an rpd crash via a crafted LDP message 1d
  • CVE-2026-101979 Junos OS and Junos OS Evolved: A network attacker causes root-level code execution or denial of service when SNMP and AAA are enabled 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-101976 is "Junos OS and Junos OS Evolved: In a non-4byte-AS scenario a specific BGP update causes an rpd crash", rated High. It affects Junos OS (Juniper Networks); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.46% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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