Adobe Connect: Improper restriction of XML external entity reference (XXE)
Summary
Adobe Connect contains an XML External Entity (XXE) injection vulnerability (CVE-2026-121887, CVSS 9.9). An authenticated attacker with a low-privileged account can send crafted XML to the server, which can lead to arbitrary code execution in the context of the current user, with a changed scope. No user interaction is required.
Affected
- Adobe Connect 0 to 12.8 (CNA record, fixed in 12.8.a)
- Adobe Connect 0 to 12.9 (CNA record, fixed in 12.9.a)
- Adobe Connect 0 to 12.10 (CNA record, fixed in 12.10.f)
- Adobe Connect 0 to 12.11 (CNA record, fixed in 12.11.i)
- Adobe Connect 0 to 12.12 (CNA record, fixed in 12.12.a)
- Bulletin APSB26-191 lists Adobe Connect 12.12 and earlier on Windows
Fixed in
- Adobe Connect 12.8.a
- Adobe Connect 12.9.a
- Adobe Connect 12.10.f
- Adobe Connect 12.11.i
- Adobe Connect 12.12.a
- Check APSB26-191 directly to confirm the fixed build for each release line.
Workaround
Unknown. No vendor-documented workaround for this CVE.
- Limit access to Adobe Connect servers from the internet.
- Remove unused accounts, especially guest and former staff accounts.
- Review logs for unusual XML or upload activity.
Exploitation
- Adobe is not aware of any exploits in the wild for the issues in bulletin APSB26-191.
- No public proof-of-concept was found at the time of research.
- The CVE was published on 10 November 2026, so the status may change quickly.
Our recommendation
- Inventory all Adobe Connect servers and clients with their exact versions.
- Patch internet-facing self-hosted servers first, to the fixed build for your release line.
- Where patching is delayed, restrict access to the server and remove unused accounts.
- Monitor logs for unusual XML processing and recheck NVD and the Adobe advisory for updates.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE record CVE-2026-121887 www.cve.org
- Adobe Security Bulletin APSB26-191 www.adobe.com
- Strix CVE-2026-121887 www.strix.ai
- OffSeq CVE-2026-121887 radar.offseq.com
- ZDI November 2026 security update review www.zerodayinitiative.com
- Adobe Security Bulletin APSB26-150 (earlier) helpx.adobe.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 10 Nov 2026, 23:24.
Original description (NVD)
Adobe Connect is affected by an Improper Restriction of XML External Entity Reference ('XXE') vulnerability that could result in arbitrary code execution in the context of the current user. A low-privileged attacker could exploit this vulnerability to execute arbitrary code. Exploitation of this issue does not require user interaction. Scope is changed.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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