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Out-of-bounds write in Juniper Session Smart Router corrupts TCP payloads

Priority LOW 21CWE-787Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

An out-of-bounds write in TCP header processing in Juniper Networks Session Smart Router lets an attacker corrupt TCP payload data and possibly cause session desynchronization. The flaw is triggered by a transit TCP packet with an oversized SACK option length, and the attack works without authentication and with no user interaction, but it is hard to carry out.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

An Out-of-Bounds Write vulnerability in the TCP header processing in Juniper Networks Session Smart Router allows an attacker to corrupt TCP payload data and potentially cause session desynchronization via a transit TCP packet with an oversized SACK option length.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00216 12th percentileScored 2026-11-07
Fix Fixed Session Smart Router (Juniper Networks): 7.0.5, 7.1.7, 7.2.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
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
JuniperSession Smart Routerbefore 7.0.5; 7.1.0 to before 7.1.7; 7.2.0 to before 7.2.37.0.5, 7.1.7, 7.2.3Patch availableCNA
  • Session Smart Router VendorJuniper Affected before 7.0.5; 7.1.0 to before 7.1.7; 7.2.0 to before 7.2.3 Fixed in 7.0.5, 7.1.7, 7.2.3 Patch available CNA

Remediation

Upgrade Juniper Networks Session Smart Router to 7.0.5, 7.1.7, or 7.2.3, which fix affected ranges before 7.0.5, from 7.1.0 before 7.1.7, and from 7.2.0 before 7.2.3.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA Session Smart Router (Juniper Networks) Fixed in 7.0.5, 7.1.7, 7.2.3

Fixed in the same release

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

  • Advisory ·

    Juniper Networks Session Smart Router — supportportal.juniper.net/JSA112183

    16 records Highest priority Priority MEDIUM 5 MEDIUM, 11 LOW

    Other records, highest priority first

    • TI-2026-82040 Missing authentication in Juniper Session Smart Router grants admin accessPriority MEDIUM 49
    • TI-2026-82044 OS command injection in Juniper Session Smart Router and ConductorPriority MEDIUM 42
    • TI-2026-82034 OS command injection in Juniper Session Smart Router and ConductorPriority MEDIUM 42

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-103392
  2. 2026-10-28 Alias added: GHSA-5q73-79v3-mp67
  3. 2026-11-05 CISA SSVC decision points changed

References

  • 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