Juniper Junos OS up to 26.2R1-S1 UTM Anti-Spam SBL stack-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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8.8$5k-$25k0.40

Summaryinfo

A vulnerability classified as very critical was found in Juniper Junos OS up to 26.2R1-S1. This affects an unknown part of the component UTM Anti-Spam SBL. Executing a manipulation can lead to stack-based overflow. This vulnerability is registered as CVE-2026-101955. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Juniper Junos OS up to 26.2R1-S1 and classified as very critical. This vulnerability affects an unknown function of the component UTM Anti-Spam SBL. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A Stack-based Buffer Overflow vulnerability in the UTM Anti-Spam SBL of Juniper Networks Junos OS on SRX series allows an unauthenticated remote attacker to cause arbitrary code execution or a denial of service via a injected malformed DNS packet when Anti-Spam SBL inspection is enabled.

The advisory is available at supportportal.juniper.net. This vulnerability was named CVE-2026-101955 since 09/28/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/14/2026).

Upgrading to version 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 eliminates this vulnerability.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 9.1
VulDB Meta Temp Score: 8.8

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.1
CNA Vector (juniper): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Junos OS 23.2R2-S7.7/23.4R2-S8.13/24.2R2-S5.5/24.4R2-S5/25.2R2-S2/25.4R1-S3/26.2R1-S2

Timelineinfo

09/28/2026 CVE reserved
10/14/2026 +16 days Advisory disclosed
10/14/2026 +0 days VulDB entry created
10/14/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: juniper.net

Advisory: supportportal.juniper.net
Status: Confirmed

CVE: CVE-2026-101955 (🔒)
GCVE (CVE): GCVE-0-2026-101955
GCVE (VulDB): GCVE-100-420070

Entryinfo

Created: 10/14/2026 18:49
Changes: 10/14/2026 18:49 (76)
Complete: 🔍
Cache ID: 216::103

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