CVE-2023-34299

Code execution via unchecked CO file length

Published May 3, 2024 · Updated Sep 18, 2024

Heap-based buffer overflow in the CO file parser in Ashlar-Vellum Cobalt 11 build 1111 allows attackers to execute code via a crafted CO file. The parser copies user-supplied data into a heap buffer without validating its length, allowing the copy to overrun the allocation. Exploitation requires a person to visit a malicious page or open a malicious file, after which code runs with the current process's privileges.

CVSS severity7.8
High
EPSS probability0.40%
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 the CO file parser in Ashlar-Vellum Cobalt 11 build 1111 allows attackers to execute code via a crafted CO file. The parser copies user-supplied data into a heap buffer without validating its length, allowing the copy to overrun the allocation. Exploitation requires a person to visit a malicious page or open a malicious file, after which code runs with the current process's privileges.

The record

CVE
CVE-2023-34299
Published
May 3, 2024
Updated
Sep 18, 2024
Vendor
Ashlar-Vellum
Product
Cobalt
Classifications
CWE-122, T1203, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2024Record 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=*
  2. Affected versionversion=Ashlar-Vellum Cobalt 11 build 1111

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Ashlar-Vellum · Cobaltversion=*; version=Ashlar-Vellum Cobalt 11 build 1111

Published CVSS scores

7.8Zero 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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution
T1204.002Malicious File

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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