CVE-2026-33165Public exploit

Heap overwrite via stale CTB metadata

Published Mar 20, 2026 · Updated Mar 20, 2026

Out-of-bounds write in libde265 before 1.0.17 allows attackers to corrupt heap memory by decoding a crafted HEVC bitstream. After an SPS size change, stale ctb_info.log2unitSize makes set_SliceHeaderIndex index beyond the allocated image metadata array. Processing attacker-supplied video is required; debug and sanitizer builds abort, while release builds silently overwrite two bytes beyond the heap allocation.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in libde265 before 1.0.17 allows attackers to corrupt heap memory by decoding a crafted HEVC bitstream. After an SPS size change, stale ctb_info.log2unitSize makes set_SliceHeaderIndex index beyond the allocated image metadata array. Processing attacker-supplied video is required; debug and sanitizer builds abort, while release builds silently overwrite two bytes beyond the heap allocation.

The record

CVE
CVE-2026-33165
Published
Mar 20, 2026
Updated
Mar 20, 2026
Vendor
Struktur AG
Product
libde265
Classifications
CWE-787, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 2026Record 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=< 1.0.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Struktur AG · libde265version=< 1.0.17

Published CVSS scores

5.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
5.5GitHub, 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-787Out-of-bounds Write
T1203Exploitation for Client Execution

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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