Medium · CVSS 5.3CVE-2026-103391

Session Smart Router: An attacker-controlled TCP option causes an out-of-bounds write when using the TCP proxy featureCVE-2026-103391

Answer in brief

CVE-2026-103391 records a Medium severity (CVSS 5.3) vulnerability in Session Smart Router: An attacker-controlled TCP option causes an out-of-bounds write when using the TCP proxy feature. The current sources do not mark it as known exploited. The current feed maps Juniper Networks/Session Smart Router (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 28, 2026Updated Oct 28, 2026Source checked Oct 28, 2026First seen by HOL Oct 28, 2026Material review Oct 28, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Juniper Networks/Session Smart Router (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Juniper Networks/Session Smart Routergeneric	>=0 <7.0.5 \|\| >=7.1.0 <7.1.7 \|\| >=7.2.0 <7.2.3	7.0.5, 7.1.7, 7.2.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for Juniper Networks/Session Smart Router.
Review the reported fix. Source-reported solution: The following software releases of Session Smart Router have been updated to resolve these specific issues: * 7.0.5 and all subsequent releases; * 7.1.7 and all subsequent releases; * 7.2.3 and all subsequent releases.

Evidence timeline and material changes

Published upstream
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 28, 2026

Sources and claim methodology

Source referencesupportportal.juniper.net

Upstream source description

An Out-of-bounds Write vulnerability in the SSR TCP proxy/optimization path in Juniper Networks Session Smart Router allows an attacker to corrupt forwarded packet data and potentially cause a data-plane crash via a transit TCP packet with a crafted TCP option length.

Quoted source text, attributed separately from HOL analysis.