DaystoPatch

FortinetExploited incident

FortiSandbox unauthenticated command injection and auth bypass (April 2026 advisories)

CVE-2026-39808, CVE-2026-39813Critical, CVSS 9.8In CISA's Known Exploited Vulnerabilities catalog since 16 Jul 2026

  • Exploited after a fix existed
FixedFixed for every supported version on the day it became public.

Response

Silence
0h
First public report to first vendor statement
Exposure
same day
First public report to first fix
Follow-through
same day
First public report to a fix for every supported version
  • Vendor silent
  • Vendor statement, no fix
  • Fixed for some versions
  • Fixed when disclosed
  • Date only, no time of day

Timeline and evidence

Open a moment to see its source and archived quote.

  1. First public report

    CVE record CVE-2026-39808 (CNA: Fortinet)CuratedQuote verified

    "datePublished":"2026-04-14T15:38:02.089Z"

    First disclosure of any CVE in the campaign (CVE-2026-39813's record followed at 15:38:30Z). Exploitation of all three CVEs was first reported by Defused on Monday 2026-06-15.

    Recorded time
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    Curated. Found by a researcher, with a verbatim quote and link.
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    Found in the archived copy
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    sha256:78e5d135b35e5bd6…
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    5 more sources for this moment
    Fortinet PSIRT FG-IR-26-100CuratedQuote not checked yet14 Apr 2026

    2026-04-14: Initial publication

    Source
    Fortinet PSIRT FG-IR-26-100 vendor advisory
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    Date only (no time of day is shown)
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    Curated. Found by a researcher, with a verbatim quote and link.
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    CVE.org record CVE-2026-39808ClaimedQuote verified14 Apr 2026, 15:38 UTC

    A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through 4.4.8 may allow attacker to execute unauthorized

    CVE record published.

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    Bluesky postClaimedQuote not checked yet14 Apr 2026, 16:27 UTC

    OS Command Injection Flaw (CVE-2026-39808)

    Earliest third-party post we hold.

    Source
    Bluesky post social
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    Claimed. The date the source gives.
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    Mastodon postClaimedQuote not checked yet16 Jun 2026, 09:39 UTC

    vulnerabilities in Fortinet's FortiSandbox platform are under active attack, with multiple flaws, including CVE-2026-39813, CVE-2026-39808, and CVE-2026-25089, being exploited by hackers just 24 hours after security updates were issued. https:// osintsights.com/fortinet-flaws -exposed-to-active-ex

    Earliest third-party post we hold.

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    Mastodon post social
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    Claimed. The date the source gives.
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    Not checked yet
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    CISA KEV (CVE-2026-39808)ClaimedQuote verified16 Jul 2026

    Fortinet FortiSandbox OS Command Injection Vulnerability

    Added to CISA's KEV catalog on 2026-07-16.

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    Claimed. The date the source gives.
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    Found in the archived copy
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    sha256:ef8fffede5c47200…
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  2. Vendor statement

    at disclosure

    CVE record CVE-2026-39808 (CNA: Fortinet)CuratedQuote verified

    "datePublished":"2026-04-14T15:38:02.089Z"

    Recorded time
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    To the minute
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
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    Found in the archived copy
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    sha256:78e5d135b35e5bd6…
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    2 more sources for this moment
    Fortinet advisory FG-IR-26-112ClaimedQuote verified14 Apr 2026

    2026-04-14: Initial publication

    From the advisory's revision history.

    Source
    Fortinet advisory FG-IR-26-112 vendor advisory
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    Claimed. The date the source gives.
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    sha256:a86824bf80a9dc3d…
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    Fortinet PSIRT FG-IR-26-100CuratedQuote not checked yet14 Apr 2026

    2026-04-14: Initial publication

    Source
    Fortinet PSIRT FG-IR-26-100 vendor advisory
    Recorded time
    Precision
    Date only (no time of day is shown)
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Not checked yet
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    No archived snapshot
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    No, kept for the record
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  3. First workaround

    No official mitigation found yet.

  4. First fix

    date onlysame day

    Fortinet PSIRT FG-IR-26-100CuratedQuote verified

    Upgrade to 4.4.9 or above

    Advisory has a single timeline entry (initial publication 2026-04-14). Upper bound: fixed builds may have shipped earlier; only the date shown here is evidenced (R2).

    Source
    Fortinet PSIRT FG-IR-26-100 vendor advisory
    Recorded time
    Precision
    Date only (no time of day is shown)
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:282c83f3c3e9ff6c…
    Used in metrics
    Yes
    Dispute this timestamp

  5. Fixed for all versions

    date onlysame day

    Fortinet PSIRT FG-IR-26-112 (CVE-2026-39813)CuratedQuote verified

    Upgrade to 5.0.6 or above

    FG-IR-26-112 (initial publication 2026-04-14, no later timeline entries) lists 5.0.6 and 4.4.9 as fixed releases; FG-IR-26-100 covers 4.4 only. Every affected line was fixed for both CVEs from 2026-04-14.

    Recorded time
    Precision
    Date only (no time of day is shown)
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:a86824bf80a9dc3d…
    Used in metrics
    Yes
    Dispute this timestamp

Send this to your boss

No brief for this incident yet. We write one for every open incident and every critical bug exploited before a fix.

Affected products

  • FortiSandbox
How we built this timeline

Grouping (revised 23 Oct 2026, R7): Defused (via Help Net Security, 16 Jun 2026: 'Attackers have been spotted exploiting three vulnerabilities (CVE-2026-39813, CVE-2026-39808, CVE-2026-25089) in FortiSandbox') reported one campaign using all three, CVE-2026-39808 and CVE-2026-39813 were disclosed the same day (14 Apr 2026) and stay together; CVE-2026-25089 (disclosed 9 Jun 2026) was split into fortinet-cve-2026-25089.

Advisories: FG-IR-26-100 (CVE-2026-39808, 14 Apr 2026, FortiSandbox 4.4 only), FG-IR-26-112 (CVE-2026-39813, 14 Apr 2026), FG-IR-26-141 (CVE-2026-25089, 9 Jun 2026, also FortiSandbox Cloud/PaaS 5.0.4-5.0.5; internally found and already fixed in 5.0.6/4.4.9). Primary CVE: no single advisory leads and CVSS ties at 9.8, so the first-disclosed KEV CVE (CVE-2026-39808) is used.

KEV lists CVE-2026-39808 and CVE-2026-25089 (16 Jul 2026); CVE-2026-39813 is not in KEV as of the cache.

All advisories still say 'Known Exploited No' (fetched 22 Oct 2026). CVSS: advisories 9.8; the CNA CVE records say 9.1.

Exploitation began after fixes existed, so exploited before a fix is false. Defused said one public exploit was 'vibecoded, and likely faulty'.

Wayback snapshots from the publication day (FG-IR-26-112 20260414184444, FG-IR-26-100 20260414215639) show 5.0.6 and 4.4.9 as plain fixed versions, not 'upcoming'.

Related

Fortinet report card