CVE-2020-12740Public exploitNetwork attack vector

Crash via unchecked IPv6 extension-header read

Published May 8, 2020 · Updated Aug 4, 2024

Heap-based buffer over-read in Tcpreplay 4.3.2 and earlier allows attackers to crash tcprewrite via a crafted PCAP file. The get_ipv6_next function reads a four-byte value from exthdr plus len without first ensuring that the address remains inside the allocated packet buffer. The attacker-supplied file must be processed by tcprewrite; observed consequences are a crash and a heap read beyond packet data.

CVSS severity9.1
Critical
EPSS probability1.65%
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 over-read in Tcpreplay 4.3.2 and earlier allows attackers to crash tcprewrite via a crafted PCAP file. The get_ipv6_next function reads a four-byte value from exthdr plus len without first ensuring that the address remains inside the allocated packet buffer. The attacker-supplied file must be processed by tcprewrite; observed consequences are a crash and a heap read beyond packet data.

The record

CVE
CVE-2020-12740
Published
May 8, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:P

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
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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