Report · Bleeping ComputerAbout CVE-2026-20262Published 15 Jun 2026

Cisco fixes SD-WAN vManage flaw exploited in zero-day attacks

Affects Cisco Catalyst SD-WAN ManagerSource Bleeping Computer

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Authoritative record:CVE-2026-20262· Medium 6.5

Exploited in the wild · KEV due 29 Jun 2026 · 29% EPSS · patch available : patch Cisco Catalyst SD-WAN Manager now.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

KEV deadline: 29 Jun 2026 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS: 29.1% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 15 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV the same day as disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE published
on cve.org
15 Jun 202616:21 UTC, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed
15 Jun 2026, the same day as disclosure
In Threat Radar
record ingested
16 Jun 202600:00 UTC, 8 hours after disclosure
KEV remediation due
US federal deadline
29 Jun 2026, 14 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

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.

Affected software

Product	Affected	Fixed in
CiscoCisco Catalyst SD-WAN Manager	Affected 17.2.4 – 26.1.1.1_LI_Images 371 affected builds	Fixed in–

Check the firmware or software version for Cisco Catalyst SD-WAN Manager in the device's admin interface against the vendor advisory.

Description

CVE-2026-20262 is a vulnerability in Cisco Catalyst SD-WAN Manager (formerly SD-WAN vManage) that allows authenticated remote attackers to create or overwrite files on the system via crafted HTTP requests, enabling escalation to root privileges. The flaw affects multiple versions across several release lines and was actively exploited in zero-day attacks. Cisco has released security updates to address this issue and strongly advises customers to apply patches. The vulnerability impacts all deployment types, including on-premises and cloud-managed environments.

Impact

Successful exploitation allows an authenticated attacker to create or overwrite any file on the filesystem of the affected system, which can be used to escalate privileges to root. This can lead to full system compromise of the Cisco Catalyst SD-WAN Manager, potentially impacting network management and security controls.

Mitigation

Cisco has released official security updates that fix this vulnerability in multiple release lines. Customers should apply the patches corresponding to their affected versions immediately. Cisco strongly advises patching to prevent exploitation. No alternative mitigations or workarounds are specified. Patch status is confirmed by Cisco's advisory.

Summary

Cisco Catalyst SD-WAN Manager contains a vulnerability (CVE-2026-20262) due to insufficient validation of user-supplied input during file uploads. An authenticated remote attacker can exploit this flaw by sending crafted HTTP requests to an affected API endpoint, allowing arbitrary file creation or overwriting on the underlying operating system. This capability can be leveraged to escalate privileges to root. The vulnerability affects multiple versions prior to fixed releases and was exploited in zero-day attacks before patches were available. Cisco's advisory includes indicators of compromise and recommends patching affected systems promptly.

CWE-22Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

bleepingcomputer.com/news/security/cisco-fixes-sd-wan-vmanage-flaw-exploited-in-zero-day-attacks/ (opens in a new tab)

Community reviews

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Exploitation evidence

Timeline

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Jun 2026, 14:13 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-22

References

Community reviews

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