CVE-2026-19781

Code execution via unchecked VS file length

Published Sep 15, 2026 · Updated Sep 15, 2026

Heap-based buffer overflow in Ashlar-Vellum Cobalt 1204.204 allows remote attackers to execute code through a crafted VS file. The VS parser copies user-supplied data into a heap buffer without first validating its length, allowing the copy to exceed the allocation. Exploitation requires the target to open the file or visit a page that supplies it, and code runs in the context of the current process.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Ashlar-Vellum Cobalt 1204.204 allows remote attackers to execute code through a crafted VS file. The VS parser copies user-supplied data into a heap buffer without first validating its length, allowing the copy to exceed the allocation. Exploitation requires the target to open the file or visit a page that supplies it, and code runs in the context of the current process.

The record

CVE
CVE-2026-19781
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Ashlar-Vellum
Product
Cobalt
Classifications
T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1204.204

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Ashlar-Vellum · Cobaltversion=1204.204

Published CVSS scores

7.8Trend Micro Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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