Heap disclosure via undersized inline-mask buffer
Published Sep 18, 2026 · Updated Sep 18, 2026
Out-of-bounds read in Struktur AG libheif before 1.23.2 allows local users to disclose heap data or crash applications through the writer API. heif_region_item_add_region_inline_mask_data() stores the caller-supplied byte count without checking it against the mask geometry, while heif_region_get_mask_image() later reads the geometry-derived length. Exploitation requires an application to construct and render an undersized inline mask; the file-parsing path validates the canonical size and is unaffected.
Summary
What happened
Out-of-bounds read in Struktur AG libheif before 1.23.2 allows local users to disclose heap data or crash applications through the writer API. heif_region_item_add_region_inline_mask_data() stores the caller-supplied byte count without checking it against the mask geometry, while heif_region_get_mask_image() later reads the geometry-derived length. Exploitation requires an application to construct and render an undersized inline mask; the file-parsing path validates the canonical size and is unaffected.
The record
- CVE
- CVE-2026-84448
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- Struktur AG
- Product
- libheif
- Classifications
- CWE-131, CWE-125, T1005
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 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?
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- Affected versionversion=< 1.23.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Inline-mask out-of-bounds read proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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