Out-of-bounds Read in Ashlar Cobalt
CVE-2025-7991
Ashlar-Vellum Cobalt VC6 File Parsing Out-Of-Bounds Read Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Ashlar-Vellum Cobalt. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of VC6 files. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated data structure. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-25945.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (9.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 9.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Ashlar Cobalt
- Ashlar-Vellum Cobalt — versions 12 SP1
Weakness classification (CWE)
References
- www.zerodayinitiative.com/advisories/ZDI-25-643/ (x_research-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2025-7991?
- CVE-2025-7991 is a high-severity vulnerability in Ashlar Cobalt, classified under Out-of-bounds Read. CVSS score: 7.8/10. Published 2025-09-17.
- How severe is CVE-2025-7991?
- High severity. CVSS v3 base score is 7.8 out of 10.