Out-of-bounds Read in Microsoft Heif Image Extension
CVE-2025-62821
Microsoft HEIF Image Extensions 1.2.22.0 has an out-of-bounds read because CHEIFItemInfoEntry_GetDataSize can return success while leaving the reported data size as 0. This causes a caller to make a 1-byte allocation. Later, CopyPixels computes copy_size = stride * abs(roi_height) but does not check the source buffer length before a memmove call.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
EPSS exploit prediction
EPSS: 0.011 (63.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000
Affected products
- Microsoft Heif Image Extension — versions 1.2.22.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/hyunjungg/CVE-2025-62821 (Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2025-62821?
- CVE-2025-62821 is a critical-severity vulnerability in Microsoft Heif Image Extension, classified under Out-of-bounds Read. CVSS score: 9.1/10. Published 2026-06-19.
- How severe is CVE-2025-62821?
- Critical severity. CVSS v3 base score is 9.1 out of 10.
- Is CVE-2025-62821 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.