CVE-2023-4256Public exploit

Local process crash via double-free cleanup

Published Dec 21, 2023 · Updated Feb 13, 2025

Double free in tcprewrite 4.4.3 and 4.4.4 allows local users to crash the process by opening a crafted Juniper Ethernet capture. During shutdown, dlt_jnpr_ether_cleanup recursively frees encoder configuration already freed and nulled by dlt_en10mb_cleanup. Execution requires a user to run tcprewrite on the crafted file; the documented consequence is an abort, not data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in tcprewrite 4.4.3 and 4.4.4 allows local users to crash the process by opening a crafted Juniper Ethernet capture. During shutdown, dlt_jnpr_ether_cleanup recursively frees encoder configuration already freed and nulled by dlt_en10mb_cleanup. Execution requires a user to run tcprewrite on the crafted file; the documented consequence is an abort, not data disclosure or modification.

The record

CVE
CVE-2023-4256
Published
Dec 21, 2023
Updated
Feb 13, 2025
Vendor
Fedora Project
Product
Fedora Linux
Classifications
CWE-415, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Fedora Project · Fedora LinuxAffected versions are unavailable in this record.
Fedora Project · Extra Packages for Enterprise LinuxAffected versions are unavailable in this record.
AppNeta · TcpreplayAffected versions are unavailable in this record.

Published CVSS scores

5.5Red Hat, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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 exploitPublished

Weakness, pattern, technique

CWE-415Double Free
T1204.002Malicious File

Public exploit references

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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