CVE-2025-20393
A vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to execute arbitrary system commands on an affected device with root privileges. This vulnerability is due to insufficient validation of HTTP requests by the Spam Quarantine feature. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Partly. The bug can be reached over the network, so generic WAF rules may stop some attacks. Its weakness type is unknown, so we cannot be more precise.
Also consider: patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2025-20393 being exploited?
Yes. CVE-2025-20393 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-2025-20393?
CVE-2025-20393 is rated Critical with a CVSS score of 10.0. 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-2025-20393?
Yes. A fix has been recorded for CVE-2025-20393. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-20393 affect?
CVE-2025-20393 affects cisco:asyncos. 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.
- affected14.0.0-698
- affected13.5.1-277
- affected13.0.0-392
- affected14.2.0-620
- affected13.0.5-007
- affected13.5.4-038
- affected14.2.1-020
- affected14.3.0-032
- affected15.0.0-104
- affected15.0.1-030
- affected15.5.0-048
- affected15.5.1-055
- affected15.5.2-018
- affected16.0.0-050
- affected15.0.3-002
- affected16.0.0-054
- affected15.5.3-022
- affected16.0.1-017
- affected13.6.2-023
- affected13.6.2-078
- affected13.0.0-249
- affected13.0.0-277
- affected13.8.1-052
- affected13.8.1-068
- affected13.8.1-074
- affected14.0.0-404
- affected12.8.1-002
- affected14.1.0-227
- affected13.6.1-201
- affected14.2.0-203
- affected14.2.0-212
- affected12.8.1-021
- affected13.8.1-108
- affected14.2.0-224
- affected14.3.0-120
- affected15.0.0-334
- affected15.5.1-024
- affected15.5.1-029
- affected15.5.2-005
- affected16.0.0-195
- affected15.5.3-017
- affected16.0.1-010
- affected15.0.1-035
- affected16.0.2-088
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: 5 GitHub proofs of concept
- StasonJatham/cisco-sa-sma-attack-N9bf4 · 22 ★
- cyberleelawat/CVE-2025-20393 · 2 ★
- KingHacker353/CVE-2025-20393 · 0 ★
- redpack-kr/Blackash-CVE-2025-20393 · 0 ★
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
- yes
- technical impact
- total
Assessed by CISA 18 Dec 2025 (SSVC 2.0.3).
timeline
- 17 Dec 2025Added to CISA KEV (exploited in the wild)
- 17 Dec 2025Published · 1 day later
- 18 Dec 2025First proof-of-concept repository on GitHub (unvetted) · same day later
- 18 Dec 2025CISA SSVC assessment: exploitation active · same day later
- 24 Dec 2025CISA remediation due date (US federal agencies) · 6 days later
- 7 Oct 2026CVE record last updated · 288 days (about 10 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 26 days later
- Linksec.cloudapps.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20393
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.