CVE-2023-40476Network attack vector

Code execution via unchecked H.265 sub-layer count

Published May 3, 2024 · Updated Nov 4, 2025

Stack-based buffer overflow in GStreamer before 1.22.6 allows remote attackers to execute code through malformed H.265 streams. In gsth265parser.c, gst_h265_parse_vps and gst_h265_parse_sps accept max_sub_layers_minus1 value 7 even though downstream storage supports only values 0 through 6. A consuming application must process the crafted stream, after which the hosting process can crash or execute attacker-controlled code.

CVSS severity8.8
High
EPSS probability2.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in GStreamer before 1.22.6 allows remote attackers to execute code through malformed H.265 streams. In gsth265parser.c, gst_h265_parse_vps and gst_h265_parse_sps accept max_sub_layers_minus1 value 7 even though downstream storage supports only values 0 through 6. A consuming application must process the crafted stream, after which the hosting process can crash or execute attacker-controlled code.

The record

CVE
CVE-2023-40476
Published
May 3, 2024
Updated
Nov 4, 2025
Vendor
GStreamer Project
Product
GStreamer
Classifications
CWE-121, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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=0 <1.22.6
  2. Affected versionversion=1.22.4 and 8dddb9ad2009705dfc3e50d59d7c56fc7314cfc3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GStreamer Project · GStreamerversion=0 <1.22.6; version=1.22.4 and 8dddb9ad2009705dfc3e50d59d7c56fc7314cfc3

Published CVSS scores

8.8Zero Day InitiativeCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
8.8NISTCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1203Exploitation for Client Execution

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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