CVE-2026-126253: Fortinet Authentication bypass by primary weakness
This Fortinet advisory covers CVE-2026-126253 in FortiOS and FortiSASE.
- CVE-2026-126253
Key facts
- Vendor rating
- Critical, CVSS 9.3
- CISA KEV
- Not listed (catalogue checked )
- Affected
- FortiOS 8.0: 8.0.0 through 8.0.1; FortiOS 7.6: 7.6.0 through 7.6.7; FortiOS 7.4: 7.4.0 through 7.4.12 and 10 more below
- Fixed in
- FortiOS 8.0: 8.0.2, FortiOS 7.6: 7.6.8, FortiOS 7.4: 7.4.13 and 8 more below
- Advisory id
- FG-IR-26-267
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
Description
CVSSv3 Score:
9.3
An Authentication Bypass by Primary Weakness vulnerability [cwe-305] in FortiOS and FortiSASE ospf daemon may allow an unauthenticated attacker to broadcast LSA via specially crafted request
Revised on 2026-11-10 00:00:00
Text from the source record.
- FortiOS 8.0: 8.0.0 through 8.0.1
- FortiOS 7.6: 7.6.0 through 7.6.7
- FortiOS 7.4: 7.4.0 through 7.4.12
- FortiOS 7.2: 7.2.0 through 7.2.13
- FortiSASE 26.3: 26.3.1
- FortiSASE 26.3: 26.3.1_a
- FortiSASE 26.2: 26.2 all versions
- FortiSASE 26.1: 26.1 all versions
- FortiSASE 25.4: 25.4 all versions
- FortiSASE 25.3: 25.3 all versions
- FortiSASE 25.2: 25.2 all versions
- FortiSASE 25.1.a: 25.1.a all versions
- FortiSASE 25.1: 25.1 all versions
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2026-126253
Upgrade to a fixed release named by Fortinet:
- FortiOS 8.0: 8.0.2
- FortiOS 7.6: 7.6.8
- FortiOS 7.4: 7.4.13
- FortiOS 7.2: 7.2.14
- FortiSASE 26.2: migrate to a fixed release
- FortiSASE 26.1: migrate to a fixed release
- FortiSASE 25.4: migrate to a fixed release
- FortiSASE 25.3: migrate to a fixed release
- FortiSASE 25.2: migrate to a fixed release
- FortiSASE 25.1.a: migrate to a fixed release
- FortiSASE 25.1: migrate to a fixed release
Vendor guidance
- Upgrade per the Affected/Solution table: FortiOS 8.0: 8.0.2; FortiOS 7.6: 7.6.8; FortiOS 7.4: 7.4.13; FortiOS 7.2: 7.2.14; FortiSASE 26.2: migrate to a fixed release; ….
Support dates for the fixed release lines
- Fortinet FortiOS 8.0: support ends
- Fortinet FortiOS 7.6: support ends
- Fortinet FortiOS 7.4: support ends
- Fortinet FortiOS 7.2: support ended
More Fortinet advisories
CVE-2026-126255Nov 10, 2026Improper neutralization of special elements in output used by a downstream componentCVE-2025-58413Nov 18, 2025stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOSCVE-2024-47569Oct 14, 2025insertion of sensitive information into sent data vulnerability in Fortinet FortiMailCVE-2026-121530Nov 10, 2026FortiOS authentication bypassCVE-2026-121530Nov 10, 2026Broken Access Control in Two-Factor-AuthenticationCVE-2026-106174Oct 13, 2026GUI Denial of Service
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