What is CVE-2026-28858?

CVE-2026-28858 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-03-25.

How severe is CVE-2026-28858?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2026-28858 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Apple iOS And Ipados

CVE-2026-28858

A buffer overflow was addressed with improved bounds checking. This issue is fixed in iOS 26.4 and iPadOS 26.4. A remote user may be able to cause unexpected system termination or corrupt kernel memory.

Vulnerability class: Buffer Overflow

Published 2026-03-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (44.4th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

Public proof-of-concept exploits

kaleth4/CVE-2026-28858

References

support.apple.com/en-us/126792 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-28858?: CVE-2026-28858 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-03-25.
How severe is CVE-2026-28858?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-28858 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.