8.8

CVE-2021-30761: Apple iOS WebKit Memory Corruption Vulnerability

CVSS: 8.8v3.1HighKEVAnalyzed
AliasesUBUNTU-CVE-2021-30761DEBIAN-CVE-2021-30761
Published 08-09-2021Last modified 21-10-2025
Open JSON

Vulnerability summary

CVE-2021-30761 is a high (CVSS 8.8) Out-of-bounds Write vulnerability in Apple iOS. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 10.54% chance of exploitation in the next 30 days, higher than 95.7% of scored vulnerabilities.

Overall risk
85/100
0100
Critical · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
10.54%
0%100%
Medium · 0.00 pp in 30 days
KEVListedCISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 5
DSA-4558-1OPENSUSE-SU-2022:0182-1RHSA-2020:4035RHSA-2020:4451RHSA-2025:10364SUSE-SU-2022:0142-1

Timeline

  1. 08-09-2021
    PublishedVulnerability first disclosed.
  2. 03-11-2021
    Added to CISA KEVApple iOS WebKit Memory Corruption Vulnerability
  3. 17-11-2021
    CISA remediation dueApply updates per vendor instructions.
  4. 21-10-2025
    Last modifiedVulnerability information updated.

Description

A memory corruption issue was addressed with improved state management. This issue is fixed in iOS 12.5.4. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

10.54%

Chance of exploitation in the next 30 days

Percentile

96%

Versus all other CVEs

30-day change

0.00 pp

From 10.54% on 19-09-2026

19-09-202619-10-2026
EPSS score
10.54%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
03-11-2021
Federal due date
17-11-2021

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-30761

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu5 products
  • qtwebkit-opensource-srcAll versions (No fix recorded)
  • qtwebkit-sourceAll versions (No fix recorded)
  • webkit2gtkAll versions (No fix recorded) | < 2.26.1-0ubuntu0.18.04.1
  • webkitgtkAll versions (No fix recorded)
  • wpewebkitAll versions (No fix recorded)
Apple2 products
Debian2 products
  • webkit2gtk< 2.26.1-2
  • wpewebkit< 2.26.3-1

3 vendors · 9 products

References

6 links