CVE Intelligence
CISA KEV Critical

CVE-2026-76504 — Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability

A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass authentication and gain access to the API as the admin user.

Published Sep 30, 2026 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: cisco

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Sep 30, 2026 Proofs of concept on GitHub · 1
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Public exploit/PoC (github)+6
  • EPSS 1.8% (30-day exploitation probability)+12
  • Technical severity (critical)+10
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Sep 30, 2026
EPSS FIRST
1.82%
ahead of 78% of scored CVEs · Oct 14, 2026
Affects
Cisco
Catalyst Sd-wan Manager
CVSS base
9.8
Critical · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

CISA required action CISA

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

US federal deadline: Oct 3, 2026 — passed 12 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Cisco Catalyst Sd-wan Manager).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  4. Apply the documented mitigations until a definitive fix is available.
  5. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Cisco Catalyst Sd-wan Manager version 20.12.8.1version 20.12.8.1.1version 20.18.4.0.5_PSIRTAUGversion 20.15.6.0.5_PSIRTAUGversion 26.1.2version 26.1.2_LI_Imagesversion 20.9.10version 20.9.10_LI_Images
and 286 more version 20.12.8.1_LI_Imagesversion 20.9.10.0.01version 20.18.4_LI_Imagesversion 20.12.8_LI_Imagesversion 20.12.8version 20.18.4version 20.18.4_LI_Imagessversion 20.15.6_LI_Imagesversion 20.15.6version 20.9.9.2_LI_Imagesversion 20.15.6.1.01version 20.12.8.2.01version 26.1.2.1.01version 20.9.9.2version 20.9.10.1.01version 20.18.4.1_LI_Imagesversion 20.15.6.1_LI_Imagesversion 26.1.2.1_LI_Imagesversion 20.18.4.1.01version 26.2.1_LI_Imagesversion 26.1.2.0.02version 20.12.7.1_LI_Imagesversion 20.15.5.2version 20.12.6.2version 20.15.5.1_LI_Imagesversion 20.15.4.3_LI_Imagesversion 20.15.4.3version 20.15.5.1version 20.12.7.1version 20.12.6.2_LI_Imagesversion 20.15.5.2_LI_Imagesversion 20.12.5.4_LI_ Imagesversion 20.12.5.4version 20.18.2.2_LI_Imagesversion 20.18.2.2version 20.9.9_LI_Imagesversion 20.9.9version 20.12.7_LI_Imagesversion 20.18.3.1version 20.12.7.2version 20.12.7.2_LI_Imagesversion 20.15.5.3_LI_Imagesversion 20.15.5.3version 20.15.4.5_LI_Imagesversion 20.15.4.5version 26.1.1.2_LI_Imagesversion 26.1.1.2version 20.12.7version 20.18.3.1_LI_Imagesversion 20.9.9.1version 20.9.9.1_LI_Imagesversion 26.1.1.1version 20.15.4.4_LI_Imagesversion 20.15.4.4version 26.1.1.1_LI_Imagesversion 20.1.12version 19.2.1version 18.4.4version 18.4.5version 20.1.1.1version 20.1.1version 19.3.0version 19.2.2version 19.2.099version 18.3.6version 18.3.7version 19.2.0version 18.3.8version 19.0.0version 19.1.0version 18.4.302version 18.4.303version 19.2.097version 19.2.098version 17.2.10version 18.3.6.1version 19.0.1aversion 18.2.0version 18.4.3version 18.4.1version 17.2.8version 18.3.3.1version 18.4.0version 18.3.1version 17.2.6version 17.2.9version 18.3.4version 17.2.5version 18.3.1.1version 18.3.5version 18.4.0.1version 18.3.3version 17.2.7version 17.2.4version 18.3.0version 19.2.3version 18.4.501_ESversion 20.3.1version 20.1.2version 19.2.929version 19.2.31version 20.3.2version 19.2.32version 20.3.2_925version 20.3.2.1version 20.3.2.1_927version 18.4.6version 20.1.2_937version 20.4.1version 20.3.2_928version 20.3.2_929version 20.4.1.0.1version 20.3.2.1_930version 19.2.4version 20.5.0.1.1version 20.4.1.1version 20.3.3version 19.2.4.0.1version 20.3.2_937version 20.3.3.1version 20.5.1version 20.1.3version 20.3.3.0.4version 20.3.3.1.2version 20.3.3.1.1version 20.4.1.2version 20.3.3.0.2version 20.4.1.1.5version 20.4.1.0.01version 20.4.1.0.02version 20.3.3.1.7version 20.3.3.1.5version 20.5.1.0.1version 20.3.3.1.10version 20.3.3.0.8version 20.4.2version 20.4.2.0.1version 20.3.4version 20.3.3.0.14version 19.2.4.0.8version 19.2.4.0.9version 20.3.4.0.1version 20.3.2.0.5version 20.6.1version 20.5.1.0.2version 20.3.3.0.17version 20.6.1.1version 20.6.0.18.3version 20.3.2.0.6version 20.6.0.18.4version 20.4.2.0.2version 20.3.3.0.16version 20.3.4.0.5version 20.6.1.0.1version 20.3.4.0.6version 20.6.2version 20.7.1EFT2version 20.3.4.0.9version 20.3.4.0.11version 20.4.2.0.4version 20.3.3.0.18version 20.7.1version 20.6.2.1version 20.3.4.1version 20.5.1.1version 20.4.2.1version 20.4.2.1.1version 20.3.4.1.1version 20.3.813version 20.3.4.0.19version 20.4.2.2.1version 20.5.1.2version 20.3.4.2version 20.3.814version 20.4.2.2version 20.6.2.2version 20.3.4.2.1version 20.7.1.1version 20.3.4.1.2version 20.6.2.2.2version 20.3.4.0.20version 20.6.2.2.3version 20.4.2.2.2version 20.3.5version 20.6.2.0.4version 20.4.2.2.3version 20.3.4.0.24version 20.6.2.2.7version 20.6.3version 20.3.4.2.2version 20.4.2.2.4version 20.7.1.0.2version 20.8.1version 20.3.5.0.8version 20.3.5.0.9version 20.4.2.2.8version 20.3.5.0.7version 20.6.3.0.7version 20.6.3.0.5version 20.6.3.0.10version 20.6.3.0.2version 20.7.2version 20.9.1EFT2version 20.6.3.0.11version 20.6.3.1version 20.6.3.0.14version 20.6.4version 20.9.1version 20.6.3.0.19version 20.6.3.0.18version 20.3.6version 20.9.1.1version 20.6.3.0.23version 20.6.4.0.4version 20.6.3.0.25version 20.6.5version 20.6.3.0.27version 20.9.2version 20.9.2.1version 20.6.3.0.29version 20.6.3.0.31version 20.6.3.0.32version 20.10.1version 20.6.3.0.33version 20.9.2.0.01version 20.9.1_LI_Imagesversion 20.10.1_LI_Imagesversion 20.9.2_LI_Imagesversion 20.3.7version 20.9.3version 20.6.5.1version 20.11.1version 20.11.1_LI_Imagesversion 20.9.3_LI_ Imagesversion 20.6.3.1.1version 20.9.3.0.2version 20.6.5.1.2version 20.9.3.0.3version 20.4.2.3version 20.6.3.2version 20.6.4.1version 20.6.3.0.38version 20.6.3.0.39version 20.3.5.1version 20.3.4.3version 20.9.3.1version 20.3.3.2version 20.6.5.2version 20.3.7.1version 20.10.1.1version 20.6.5.2.1version 20.3.4.0.25version 20.6.2.2.4version 20.6.1.2version 20.11.1.1version 20.9.3.0.5version 20.3.4.0.26version 20.6.5.1.3version 20.6.3.0.40version 20.1.3.1version 20.9.2.2version 20.6.5.2.3version 20.6.5.1.4version 20.6.5.3version 20.6.3.0.41version 20.9.3.0.7version 20.6.5.1.5version 20.9.3.0.4version 20.6.4.0.19version 20.6.5.1.6version 20.9.3.0.8version 20.6.3.3version 20.3.7.2version 20.6.5.4version 20.6.5.1.7version 20.9.3.0.12version 20.6.4.2version 20.6.5.5version 20.9.3.2version 20.11.1.2version 20.6.3.4version 20.10.1.2version 20.6.5.1.9version 20.9.3.0.16version 20.6.3.0.45version 20.6.5.1.10
Vulnerable CVE Program (cve.org) e CISA ADP
Cisco Catalyst Sd-wan Manager version 26.2≥ 26.1 and < 26.1.2.1≥ 20.18 and < 20.18.4.1≥ 20.15 and < 20.15.6.1≥ 20.12 and < 20.12.8.2< 20.9.10.1 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.8 CVSS 3.1 Critical 3.9 5.9 psirt@cisco.com via NIST National Vulnerability Database
9.8 CVSS 3.1 Critical — — GitHub, Inc. via GitHub Security Advisories
9.8 CVSS 3.1 Critical — — cisco via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-177

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Sep 30, 2026
Federal deadline
Oct 3, 2026
passed 12 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Proofs of concept on GitHub

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 1.82%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Hunt retroactively in logs from before Sep 30, 2026 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • Affected products added · cisco/catalyst sd-wan manager
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 13, 2026
  • Affected products added · cisco/cisco catalyst sd-wan manager
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • CVSS changed · 9.8
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • CVE published
    Sep 30, 2026 · cisco
  • Added to CISA KEV catalog
    Sep 29, 2026 · CISA

Source activity

Repeated readings are counted rather than listed.

  • 3× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

Cisco
every CVE for this vendor
2026-09
what else CISA listed that month
CWE-177
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20262 Cisco Catalyst SD-WAN Manager Directory or Path Traversal Vulnerability KEV Jun 15, 2026
  • CVE-2026-20245 Cisco Catalyst SD-WAN Manager Improper Encoding or Escaping of Output Vulnerability KEV Jun 4, 2026
  • CVE-2026-20224 Cisco Catalyst SD-WAN Manager XML External Entity Injection Vulnerability May 14, 2026
  • CVE-2026-20210 Cisco Catalyst SD-WAN Manager Privilege Escalation Vulnerability May 14, 2026
  • CVE-2026-20182 Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability KEV May 14, 2026
  • CVE-2026-20209 Cisco Catalyst SD-WAN Manager Privilege Escalation Vulnerability May 14, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-76504 is "Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability", rated Critical. It affects Catalyst Sd-wan Manager (Cisco); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 1.82% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.