Cisco Unified CM Flaw CVE-2026-20230 Actively Exploited in the Wild


Cisco Unified CM Flaw CVE-2026-20230 Actively Exploited in the Wild

Pierluigi Paganini
June 24, 2026

Attackers exploit Cisco Unified CM flaw (CVE-2026-20230) allowing unauth HTTP requests to trigger SSRF, write files, and gain root access

Cisco Unified Communications Manager has a serious vulnerability, tracked as CVE-2026-20230 (CVSS score of 8.6), that attackers are already exploiting. The flaw, caused by improper validation of certain HTTP requests, allows a remote attacker without authentication to perform server-side request forgery (SSRF) attacks. Early June, Cisco warned that public PoC code is available and that successful exploitation could allow attackers to write files that may later be used to gain root privileges.

This makes affected systems high risk if exposed. Be careful.

“This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device.” reads the advisory. “A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root.”

Cisco rated this advisory as Critical instead of High because successful exploitation could allow an attacker to escalate privileges to root. However, the risk depends on configuration: the vulnerability can only be exploited if the WebDialer service is enabled, which is disabled by default on affected systems.

There is no full workaround for this vulnerability. The networking giant recommends mitigating risk by disabling the WebDialer service until a patch is applied. Administrators can do this through the Unified CM Administration interface by going to Unified Serviceability, opening Service Activation under Tools, and unchecking the WebDialer Web Service option in the CTI Services section before saving the changes.

Below are the fixed releases:

Cisco Unified CM and Unified CM SME Release First Fixed Release
14 14SU6
15 15SU5 (Sep 2026) or COP1

The company confirms that PoC exploit code for the vulnerability is publicly available. However, the PSIRT is not aware of attacks in the wild exploiting this issue.

This week, Defused Cyber researchers confirmed it observed active exploitation of the issue in attacks in the wild.

“Over the weekend we observed exploitation of CVE-2026-20230 – Cisco Unified CM (CUCM) WebDialer SSRF → root file-write (CVSS 8.6)” the researchers wrote on X. “No previously recorded exploitation, and not yet listed in CISA KEV.

This is currently being exploited from a single source using an unvetted PoC, with genuinely-formatted file:// file-write payloads landing on our decoys. Track Cisco CUCM exploitation”

At this time, Cisco PSIRT has yet to confirm active exploitation of the flaw.

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, CVE-2026-20230)







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I am a recent convert to physical media — yet even as someone getting back into buying discs in 2026, I haven’t been buying Blu-rays. Like many Americans, I still pick up DVDs instead. These aren’t great times for the Blu-ray format, and don’t expect a turnaround in 2026.

Fewer new releases make their way to Blu-ray

More media is now released exclusively for streaming

Blu-ray has been around for two decades, but it never managed to fully replace, or even overtake, the DVD format it was designed to supersede. We still can’t take for granted that our favorite movies, let alone TV shows, will eventually see a Blu-ray release.

The movies most likely to come to Blu-ray are the ones that hit theaters, but a growing amount of cinema is designed exclusively with streaming platforms in mind. I recently rewatched Mississippi Masala, which led me to check in on what work Sarita Choudhury has done over the decades since. A film called Evil Eye released in 2020 caught my eye. Unfortunately, it’s only available via Prime Video. There’s no Blu-ray or even a DVD. In contrast, it’s easy to watch Michael B. Jordan in Sinners on Blu-ray, since that movie came to theaters last year.

You could say that it makes sense that a movie with a 4.8/10 rating on IMDb doesn’t see a physical release, but in the heyday of physical video, store shelves were stacked not only with just the big-budget bangers but plenty of straight-to-DVD movies as well. Now those films exist to pad out streaming catalogs instead.

Fewer big box stores stock their shelves with physical discs

Blu-ray discs have disappeared from some stores entirely

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If you venture onto Reddit and visit r/Blu-ray, you will find more threads about thrift store hauls and older collections than excitement over the latest new release. Don’t get me wrong — I, too, am very excited about seeing what gems I can snag for only a couple bucks, but this shows the challenge retailers face. Increasingly, only enthusiasts are prepared to drop over $20 on a disc.

I’m not buying discs to stick them in a player

Phone on a stand playing a Netflix video Credit: Bertel King / How-To Geek

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The industry isn’t helping itself, either. 4K Ultra HD Blu-ray discs come with DRM and aren’t easy to play on a modern PC, further limiting potential growth. They do not want anyone pirating these super high-quality versions. When you consider that some of these 4K Blu-rays have an AI upscaling problem, you’re paying more for what may not even be the best version.​​​​​​​


Blu-ray is seeing fewer releases, is available in fewer places, and is less accessible in the ways many of us want to watch TV shows and movies in 2026. With our portable devices getting better and internet speeds getting faster, it’s hard to see physical video staging a turnaround, even if we’re still a long way off from it going away entirely.



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