Medium Memory corruption

CVE-2026-33799 — Junos OS and Junos OS Evolved: Receipt of a specific SNMPv3 request results in memory leak and eventual snmpd crash

An Out-of-bounds Write vulnerability in the SNMP daemon (snmpd) of Juniper Networks Junos OS and Junos OS Evolved allows an authenticated network-based attacker sending specific valid SNMPv3 queries to trigger a memory leak. Over time, continuous receipt of these queries will result in snmpd process memory exhaustion, resulting in a process crash and restart, impacting the ability to monitor the system via SNMP. Memory usage can be monitored using the following command: user@device> show system processes extensive | match snmpd This issue affects: Junos OS: * all versions before 21.2R3-S8; * from 21.4 before 21.4R3-S7; * from 22.1 before 22.1R3-S6; * from 22.2 before 22.2R3-S4; * from 22.3 before 22.3R3-S3; * from 22.4 before 22.4R3-S2; * from 23.2 before 23.2R2; * from 23.4 before 23.4R2. Junos OS Evolved: * all versions before 21.2R3-S8-EVO; * from 21.4 before 21.4R3-S7-EVO; * all versions of 22.1-EVO, * from 22.2 before 22.2R3-S4-EVO; * from 22.3 before 22.3R3-S3-EVO; * all versions of 22.4-EVO, * from 23.2 before 23.2R2-EVO; * from 23.4 before 23.4R2-EVO.

Published Jul 9, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: juniper

Low

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

Technical severity (medium)+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

—

No EPSS score.

Affects

Juniper Networks

Junos and 2 more

CVSS base

4.3

Medium · 2 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

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.

Documented mitigation — supportportal.juniper.net (NIST National Vulnerability Database)

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.

Identify exposed assets running the affected vendor/product/version combinations (Juniper Networks Junos, Juniper Networks Junos OS, Juniper Networks Junos Os Evolved).
Apply the documented mitigations until a definitive fix is available.
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.

Vendor	Product	Versions	Status	Source
Juniper Networks	Junos	< 21.2version 21.2version 21.2-r1version 21.2-r1-s1version 21.2-r1-s2version 21.2-r2version 21.2-r2-s1version 21.2-r2-s2 and 72 more version 21.2-r3version 21.2-r3-s1version 21.2-r3-s2version 21.2-r3-s3version 21.2-r3-s4version 21.2-r3-s5version 21.2-r3-s6version 21.2-r3-s7version 21.4version 21.4-r1version 21.4-r1-s1version 21.4-r1-s2version 21.4-r2version 21.4-r2-s1version 21.4-r2-s2version 21.4-r3version 21.4-r3-s1version 21.4-r3-s2version 21.4-r3-s3version 21.4-r3-s4version 21.4-r3-s5version 21.4-r3-s6version 22.1version 22.1-r1version 22.1-r1-s1version 22.1-r1-s2version 22.1-r2version 22.1-r2-s1version 22.1-r2-s2version 22.1-r3version 22.1-r3-s1version 22.1-r3-s2version 22.1-r3-s3version 22.1-r3-s4version 22.1-r3-s5version 22.2version 22.2-r1version 22.2-r1-s1version 22.2-r1-s2version 22.2-r2version 22.2-r2-s1version 22.2-r2-s2version 22.2-r3version 22.2-r3-s1version 22.2-r3-s2version 22.2-r3-s3version 22.3version 22.3-r1version 22.3-r1-s1version 22.3-r1-s2version 22.3-r2version 22.3-r2-s2version 22.3-r3version 22.3-r3-s1version 22.3-r3-s2version 22.4version 22.4-r1version 22.4-r1-s1version 22.4-r1-s2version 22.4-r2version 22.4-r2-s1version 22.4-r2-s2version 22.4-r3version 22.4-r3-s1version 23.2version 23.2-r1version 23.2-r1-s1version 23.2-r1-s2version 23.4version 23.4-r1version 23.4-r1-s1version 23.4-r1-s2	Vulnerable	NIST National Vulnerability Database
Juniper Networks	Junos OS	< 21.2R3-S8≥ 21.4 and < 21.4R3-S7≥ 22.1 and < 22.1R3-S6≥ 22.2 and < 22.2R3-S4≥ 22.3 and < 22.3R3-S3≥ 22.4 and < 22.4R3-S2≥ 23.2 and < 23.2R2≥ 23.4 and < 23.4R2	Vulnerable	CVE Program (cve.org) e CISA ADP
Juniper Networks	Junos Os Evolved	< 21.2version 21.2version 21.2-r1version 21.2-r1-s1version 21.2-r1-s2version 21.2-r2version 21.2-r2-s1version 21.2-r2-s2 and 52 more version 21.2-r3version 21.2-r3-s1version 21.2-r3-s2version 21.2-r3-s3version 21.2-r3-s4version 21.2-r3-s5version 21.2-r3-s6version 21.2-r3-s7version 21.4version 21.4-r1version 21.4-r1-s1version 21.4-r1-s2version 21.4-r2version 21.4-r2-s1version 21.4-r2-s2version 21.4-r3version 21.4-r3-s1version 21.4-r3-s2version 21.4-r3-s3version 21.4-r3-s4version 23.4-r1-s1version 22.3-r3-s1version 22.3-r3-s2version 22.4version 23.2version 23.2-r1version 23.2-r1-s1version 23.2-r1-s2version 23.4version 23.4-r1version 22.3-r3version 23.4-r1-s2version 22.2-r3version 21.4-r3-s6version 22.1version 22.2version 22.2-r1version 22.2-r1-s1version 22.2-r1-s2version 22.2-r2version 22.2-r2-s1version 22.2-r2-s2version 21.4-r3-s5version 22.2-r3-s1version 22.2-r3-s2version 22.2-r3-s3version 22.3version 22.3-r1version 22.3-r1-s1version 22.3-r1-s2version 22.3-r2version 22.3-r2-s2	Vulnerable	NIST National Vulnerability Database
Juniper Networks	Junos Os Evolved	< 21.2R3-S8-EVO≥ 21.4 and < 21.4R3-S7-EVO≥ 22.1 and < 22.1≥ 22.2 and < 22.2R3-S4-EVO≥ 22.3 and < 22.3R3-S3-EVO≥ 22.4 and < 22.4≥ 23.2 and < 23.2R2-EVO≥ 23.4 and < 23.4R2-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

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
5.3	CVSS 4.0	Medium	—	—	sirt@juniper.net via NIST National Vulnerability Database
5.3	CVSS 4.0	Medium	—	—	juniper via CVE Program (cve.org) e CISA ADP
4.3	CVSS 3.1	Medium	2.8	1.4	sirt@juniper.net via NIST National Vulnerability Database
4.3	CVSS 3.1	Medium	—	—	juniper via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L (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
Affected products added · juniper networks/junos os, juniper networks/junos os evolved
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 4.3
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Jul 9, 2026 · juniper

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

supportportal.juniper.net/JSA110074
Mitigation, Vendor Advisory, vendor-advisory, NIST National Vulnerability Database

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)

Critical 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
High 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
Critical CVE-2026-101983 Junos OS and Junos OS Evolved: An attacker causes remote code execution when J-Web virtual-domain is configured 1d
Medium CVE-2026-101964 Junos OS and Junos OS Evolved: An attacker can cause an rpd crash via a crafted LDP message 1d
Medium CVE-2026-101975 Junos OS and Junos OS Evolved: Improper OSPF LSA validation causes an rpd crash when prefix-SID best-route installation is used 1d
Medium CVE-2026-101972 Junos OS and Junos OS Evolved: Malformed OSPF packets causes routing disruption when OSPF is 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 FIRST EPSS score.
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-2026-33799 is "Junos OS and Junos OS Evolved: Receipt of a specific SNMPv3 request results in memory leak and eventual snmpd crash", rated Medium. It affects Junos (Juniper Networks); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. 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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