Skip to content
vulnerability

CVE-2025-20333

9.9
Critical
KEV · Exploited in wildEPSS 71%Patch available

A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.

exploited
Yes, in CISA KEV since 25 Sept 2025fix by 26 Sept 2025 (CISA deadline for US federal agencies)unvetted proof-of-concept code on github
fix
Patch available see the advisory in the references
likelihood
EPSS 71.2%
Published 25 Sept 2025Analysed here 2 Nov 2026CVSS scored by the publisher (CNA)

do firstThe KEV due date refers to the deadline by which FCEB agencies are expected to review and begin implementing the guidance outlined in Emergency Directive (ED) 25-03 (URL listed below in Notes). Agencies must follow the mitigation steps provided by CISA (URL listed below in Notes) and vendor’s instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

triage
server-sideruntimeWAF can block: partlyAV · networkCWE-120· Buffer Overflow

Can a WAF block it? Partly. Cloudflare publishes WAF rules written for this CVE. Such rules block the known exploit requests and buy time, but attackers can change the request to get past them, so they do not replace the patch.

Also consider: patch · enable the vendor rule in block mode

Based on WAF vendor rules published for this CVE. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

cvss vector
attack vectornetworkattack complexitylowprivileges requiredlowuser interactionnonescopechangedconfidentialityhighintegrityhighavailabilityhigh
CVSS 3.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
common questions

Is CVE-2025-20333 being exploited?

Yes. CVE-2025-20333 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2025-20333?

CVE-2025-20333 is rated Critical with a CVSS score of 9.9. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2025-20333?

Yes. A fix has been recorded for CVE-2025-20333. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2025-20333 affect?

CVE-2025-20333 affects cisco:adaptive_security_appliance_software, cisco:secure_firewall_threat_defense. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
cisco:adaptive_security_appliance_softwarecisco:secure_firewall_threat_defense
affected versions
Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
  • affected9.8.1
  • affected9.8.1.5
  • affected9.8.1.7
  • affected9.8.2
  • affected9.8.2.8
  • affected9.8.2.14
  • affected9.8.2.15
  • affected9.8.2.17
  • affected9.8.2.20
  • affected9.8.2.24
  • affected9.8.2.26
  • affected9.8.2.28
  • affected9.8.2.33
  • affected9.8.2.35
  • affected9.8.2.38
  • affected9.8.3.8
  • affected9.8.3.11
  • affected9.8.3.14
  • affected9.8.3.16
  • affected9.8.3.18
  • affected9.8.3.21
  • affected9.8.3
  • affected9.8.3.26
  • affected9.8.3.29
  • affected9.8.4
  • affected9.8.4.3
  • affected9.8.4.7
  • affected9.8.4.8
  • affected9.8.4.10
  • affected9.8.4.12
  • affected9.8.4.15
  • affected9.8.4.17
  • affected9.8.2.45
  • affected9.8.4.25
  • affected9.8.4.20
  • affected9.8.4.22
  • affected9.8.4.26
  • affected9.8.4.29
  • affected9.8.4.32
  • affected9.8.4.33
  • affected9.8.4.34
  • affected9.8.4.35
  • affected9.8.4.39
  • affected9.8.4.40
  • affected9.8.4.41
  • affected9.8.4.43
  • affected9.8.4.44
  • affected9.8.4.45
  • affected9.8.4.46
  • affected9.8.4.48
  • affected9.12.1
  • affected9.12.1.2
  • affected9.12.1.3
  • affected9.12.2
  • affected9.12.2.4
  • affected9.12.2.5
  • affected9.12.2.9
  • affected9.12.3
  • affected9.12.3.2
  • affected9.12.3.7
  • affected9.12.4
  • affected9.12.3.12
  • affected9.12.3.9
  • affected9.12.2.1
  • affected9.12.4.2
  • affected9.12.4.4
  • affected9.12.4.7
  • affected9.12.4.10
  • affected9.12.4.13
  • affected9.12.4.8
  • affected9.12.4.18
  • affected9.12.4.24
  • affected9.12.4.26
  • affected9.12.4.29
  • affected9.12.4.30
  • affected9.12.4.35
  • affected9.12.4.37
  • affected9.12.4.38
  • affected9.12.4.39
  • affected9.12.4.40
  • affected9.12.4.41
  • affected9.12.4.47
  • affected9.12.4.48
  • affected9.12.4.50
  • affected9.12.4.52
  • affected9.12.4.54
  • affected9.12.4.55
  • affected9.12.4.56
  • affected9.12.4.58
  • affected9.12.4.62
  • affected9.12.4.65
  • affected9.12.4.67
  • affected9.14.1
  • affected9.14.1.10
  • affected9.14.1.6
  • affected9.14.1.15
  • affected9.14.1.19
  • affected9.14.1.30
  • affected9.14.2
  • affected9.14.2.4
  • affected9.14.2.8
  • affected9.14.2.13
  • affected9.14.2.15
  • affected9.14.3
  • affected9.14.3.1
  • affected9.14.3.9
  • affected9.14.3.11
  • affected9.14.3.13
  • affected9.14.3.18
  • affected9.14.3.15
  • affected9.14.4
  • affected9.14.4.6
  • affected9.14.4.7
  • affected9.14.4.12
  • affected9.14.4.13
  • affected9.14.4.14
  • affected9.14.4.15
  • affected9.14.4.17
  • affected9.14.4.22
  • affected9.14.4.23
  • affected9.14.4.24
  • affected9.16.1
  • affected9.16.1.28
  • affected9.16.2
  • affected9.16.2.3
  • affected9.16.2.7
  • affected9.16.2.11
  • affected9.16.2.13
  • affected9.16.2.14
  • affected9.16.3
  • affected9.16.3.3
  • affected9.16.3.14
  • affected9.16.3.15
  • affected9.16.3.19
  • affected9.16.3.23
  • affected9.16.4
  • affected9.16.4.9
  • affected9.16.4.14
  • affected9.16.4.18
  • affected9.16.4.19
  • affected9.16.4.27
  • affected9.16.4.38
  • affected9.16.4.39
  • affected9.16.4.42
  • affected9.16.4.48
  • affected9.16.4.55
  • affected9.16.4.57
  • affected9.16.4.61
  • affected9.16.4.62
  • affected9.16.4.67
  • affected9.16.4.70
  • affected9.16.4.71
  • affected9.16.4.76
  • affected9.16.4.82
  • affected9.16.4.84
  • affected9.17.1
  • affected9.17.1.7
  • affected9.17.1.9
  • affected9.17.1.10
  • affected9.17.1.11
  • affected9.17.1.13
  • affected9.17.1.15
  • affected9.17.1.20
  • affected9.17.1.30
  • affected9.17.1.33
  • affected9.17.1.39
  • affected9.18.1
  • affected9.18.1.3
  • affected9.18.2
  • affected9.18.2.5
  • affected9.18.2.7
  • affected9.18.2.8
  • affected9.18.3
  • affected9.18.3.39
  • affected9.18.3.46
  • affected9.18.3.53
  • affected9.18.3.55
  • affected9.18.3.56
  • affected9.18.4
  • affected9.18.4.5
  • affected9.18.4.8
  • affected9.18.4.22
  • affected9.18.4.24
  • affected9.18.4.29
  • affected9.18.4.34
  • affected9.18.4.40
  • affected9.19.1
  • affected9.19.1.5
  • affected9.19.1.9
  • affected9.19.1.12
  • affected9.19.1.18
  • affected9.19.1.22
  • affected9.19.1.24
  • affected9.19.1.27
  • affected9.19.1.28
  • affected9.19.1.31
  • affected9.20.1
  • affected9.20.1.5
  • affected9.20.2
  • affected9.20.2.10
  • affected9.20.2.21
  • affected9.20.2.22
  • affected9.20.3
  • affected9.20.3.4
  • affected9.22.1.1
  • affected9.22.1.2
Cisco Cisco Secure Firewall Threat Defense (FTD) Software
  • affected6.2.3
  • affected6.2.3.1
  • affected6.2.3.2
  • affected6.2.3.3
  • affected6.2.3.4
  • affected6.2.3.5
  • affected6.2.3.6
  • affected6.2.3.7
  • affected6.2.3.8
  • affected6.2.3.10
  • affected6.2.3.11
  • affected6.2.3.9
  • affected6.2.3.12
  • affected6.2.3.13
  • affected6.2.3.14
  • affected6.2.3.15
  • affected6.2.3.16
  • affected6.2.3.17
  • affected6.2.3.18
  • affected6.6.0
  • affected6.6.0.1
  • affected6.6.1
  • affected6.6.3
  • affected6.6.4
  • affected6.6.5
  • affected6.6.5.1
  • affected6.6.5.2
  • affected6.6.7
  • affected6.6.7.1
  • affected6.6.7.2
  • affected6.4.0
  • affected6.4.0.1
  • affected6.4.0.3
  • affected6.4.0.2
  • affected6.4.0.4
  • affected6.4.0.5
  • affected6.4.0.6
  • affected6.4.0.7
  • affected6.4.0.8
  • affected6.4.0.9
  • affected6.4.0.10
  • affected6.4.0.11
  • affected6.4.0.12
  • affected6.4.0.13
  • affected6.4.0.14
  • affected6.4.0.15
  • affected6.4.0.16
  • affected6.4.0.17
  • affected6.4.0.18
  • affected7.0.0
  • affected7.0.0.1
  • affected7.0.1
  • affected7.0.1.1
  • affected7.0.2
  • affected7.0.2.1
  • affected7.0.3
  • affected7.0.4
  • affected7.0.5
  • affected7.0.6
  • affected7.0.6.1
  • affected7.0.6.2
  • affected7.0.6.3
  • affected7.0.7
  • affected7.0.8
  • affected7.1.0
  • affected7.1.0.1
  • affected7.1.0.2
  • affected7.1.0.3
  • affected7.2.0
  • affected7.2.0.1
  • affected7.2.1
  • affected7.2.2
  • affected7.2.3
  • affected7.2.4
  • affected7.2.4.1
  • affected7.2.5
  • affected7.2.5.1
  • affected7.2.6
  • affected7.2.7
  • affected7.2.5.2
  • affected7.2.8
  • affected7.2.8.1
  • affected7.3.0
  • affected7.3.1
  • affected7.3.1.1
  • affected7.3.1.2
  • affected7.4.0
  • affected7.4.1
  • affected7.4.1.1
  • affected7.4.2
  • affected7.4.2.1
  • affected7.4.2.2
  • affected7.4.2.3
  • affected7.6.0

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

public exploits

Unvetted proof-of-concept code on GitHub: 3 GitHub proofs of concept

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

cisa ssvc

exploitation
active
automatable
no
technical impact
total

Assessed by CISA 26 Sept 2025 (SSVC 2.0.3).

timeline

  1. 25 Sept 2025Added to CISA KEV (exploited in the wild)
  2. 25 Sept 2025Published · 1 day later
  3. 26 Sept 2025CISA remediation due date (US federal agencies) · same day later
  4. 26 Sept 2025CISA SSVC assessment: exploitation active · same day later
  5. 26 Feb 2026CVE record last updated · 154 days (about 5 months) later
  6. 16 May 2026First proof-of-concept repository on GitHub (unvetted) · 78 days (about 3 months) later
  7. 2 Nov 2026Analysed by vulneraibility.com · 171 days (about 6 months) later
how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
NVDCVE.orgCVE DetailsSource
3 references in the CVE record: 1 advisory, 2 links

sources

  • CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
  • NVD: CVSS and CPE data
  • CISA KEV catalog: exploitation, date added, due date
  • CISA Vulnrichment (ADP): SSVC decision points
  • FIRST EPSS: exploit probability and percentile
  • PoC-in-GitHub: GitHub repositories that claim a proof of concept
  • Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
get alerted

Track only the vulnerabilities that affect your infrastructure.

start for free

© 2026 vulneraibility.com, all rights reserved