CVE-2020-9948: A type confusion issue was addressed with improved memory handling

Q: How do I fix CVE-2020-9948?

safari: upgrade to 14.0; webkitgtk\+: upgrade to newer than 2.30.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-9948 being exploited?

CVE-2020-9948 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-9948 affect?

CVE-2020-9948 affects safari, webkitgtk\+, debian linux. Severity is high (CVSS 8.8). A type confusion issue was addressed with improved memory handling. This issue is fixed in Safari 14.0. Processing maliciously crafted web content may lead to arbitrary code execution.

Q: How urgent is CVE-2020-9948?

Priority 55/100. High severity; On your watchlist

This month

HIGH 8.8WATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2020-9948 is a high-severity flaw (CVSS 8.8) affecting safari, webkitgtk\+, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A type confusion issue was addressed with improved memory handling. This issue is fixed in Safari 14.0. Processing maliciously crafted web content may lead to arbitrary code execution.

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-843
Published	2020-10-16
Last modified	2026-06-17

Publisher (CNA): Apple Inc. · Vendor: apple · debian · webkit

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-10-16 17:15 UTCPublished CVE record published
2026-06-17 03:28 UTCUpdated Record last modified

apple safari UPGRADE

Affected: < 14.0

Fixed in: 14.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy safari || rpm -q safari || safari --version

2. UPGRADE to 14.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade safari

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade safari

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

webkit webkitgtk\+ UPGRADE

Affected: <= 2.30.3

Fixed in: newer than 2.30.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy webkitgtk+ || rpm -q webkitgtk+ || webkitgtk+ --version

2. UPGRADE to newer than 2.30.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade webkitgtk+

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade webkitgtk+

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-9948?

safari: upgrade to 14.0; webkitgtk\+: upgrade to newer than 2.30.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-9948 being exploited?

CVE-2020-9948 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-9948 affect?

CVE-2020-9948 affects safari, webkitgtk\+, debian linux. Severity is high (CVSS 8.8). A type confusion issue was addressed with improved memory handling. This issue is fixed in Safari 14.0. Processing maliciously crafted web content may lead to arbitrary code execution.

How urgent is CVE-2020-9948?

Priority 55/100. High severity; On your watchlist

Software pages

Debian vulnerabilities · Safari vulnerabilities · WebKit vulnerabilities · Apple Safari and WebKit vulnerabilities

Related CVEs

CVE-2023-43000 HIGH 8.8 EXPLOITED UPGRADE UPGRADE Apple Multiple products Use-After-Free Vulnerability
CVE-2026-43715 HIGH 8.8 UPGRADE UPGRADE A use-after-free issue was addressed with improved memory management
CVE-2025-43342 CRITICAL 9.8 UPGRADE UPGRADE A correctness issue was addressed with improved checks
CVE-2025-43343 CRITICAL 9.8 UPGRADE UPGRADE The issue was addressed with improved memory handling
CVE-2025-43376 HIGH 7.5 UPGRADE UPGRADE A logic issue was addressed with improved state management

References

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