CVE-2023-31102Public exploit

Code execution via PPMd decoder integer underflow

Published Nov 3, 2023 · Updated Sep 6, 2024

Integer underflow in 7-Zip before 23.00 allows remote attackers to execute code after a user opens a crafted 7Z archive. In Ppmd7.c, a crafted PPMd stream reaches SetSuccessor with unsigned numPs at zero; decrementing it wraps the value and indexes ps out of bounds, causing an invalid read. Opening the archive is required; the published proof of concept demonstrates a segmentation-fault crash, while ZDI reports code execution in the current process.

CVSS severity7.8
High
EPSS probability57.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in 7-Zip before 23.00 allows remote attackers to execute code after a user opens a crafted 7Z archive. In Ppmd7.c, a crafted PPMd stream reaches SetSuccessor with unsigned numPs at zero; decrementing it wraps the value and indexes ps out of bounds, causing an invalid read. Opening the archive is required; the published proof of concept demonstrates a segmentation-fault crash, while ZDI reports code execution in the current process.

The record

CVE
CVE-2023-31102
Published
Nov 3, 2023
Updated
Sep 6, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-191, T1203, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 6, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8CISA-ADPCVSS:3.1/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 exploitPublished

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
T1203Exploitation for Client Execution
T1204.002User Execution: Malicious 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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