CVE-2023-4720Public exploit

Crash via signed left shift in SWF parser

Published Sep 1, 2023 · Updated Sep 19, 2024

Undefined behavior in GPAC before 2.3-DEV allows local users to crash MP4Box by processing a crafted SWF file. In swf_get_s16 in scene_manager/swf_parse.c, a signed 8-bit value can be negative before the function left-shifts it by eight bits, invoking undefined behavior. The issue is reached when MP4Box's DASH path parses attacker-supplied SWF content; published assessments report no data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Undefined behavior in GPAC before 2.3-DEV allows local users to crash MP4Box by processing a crafted SWF file. In swf_get_s16 in scene_manager/swf_parse.c, a signed 8-bit value can be negative before the function left-shifts it by eight bits, invoking undefined behavior. The issue is reached when MP4Box's DASH path parses attacker-supplied SWF content; published assessments report no data disclosure or modification.

The record

CVE
CVE-2023-4720
Published
Sep 1, 2023
Updated
Sep 19, 2024
Vendor
GPAC Project
Product
GPAC
Classifications
CWE-1077, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 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=unspecified <2.3-DEV

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

GPAC Project · GPACversion=unspecified <2.3-DEV

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.0huntr.devCVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1077Floating Point Comparison with Incorrect Operator
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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