CVE-2026-121742: Ashlar-Vellum Cobalt · Use After Free
Affects Ashlar-Vellum CobaltSource CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 12 Nov 2026, 03:04 UTC
Thin evidence
One scorer or none| CNA (zdi) | CVSS 3.0 | 7.8 |
|---|
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 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: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Ashlar-VellumCobalt | Affected
| Fixed in– |
AI-suggested
Until a fix is available, users should avoid opening untrusted XE files or visiting untrusted pages that could trigger this vulnerability.
Description
CVE-2026-121742 is a use-after-free vulnerability in Ashlar-Vellum Cobalt XE file parsing that allows remote attackers to execute arbitrary code. Exploitation requires user interaction, such as opening a malicious file or visiting a malicious page. The flaw arises from operations on objects without validating their existence, leading to potential code execution in the context of the current process.