CVE
CVE-2021-30761
Apple iOS WebKit Memory Corruption Vulnerability
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..
HIGH · CVSS 8.8
⚠ CISA KEV
EPSS 0.00331
Act now
- Listed on CISA KEV (known exploited in the wild)
- SSVC exploitation status: active
- Public exploit or PoC is available
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
▸
How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2021-30761, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
⬢
Required Remediation
Apply updates per vendor instructions.
◆
ATT&CK techniques
2Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniques⬡
Weakness Classification
CWE-787Out-of-bounds Write
CWE-787Out-of-bounds Write
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Affected Products & Versions
1apple iphone os< 12.5.4
▤
Affected Packages
14Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Ubuntu:18.04:LTS
webkit2gtk
fixed in 2.26.1-0ubuntu0.18.04.1
Ubuntu:20.04:LTS
qtwebkit-opensource-src
Ubuntu:20.04:LTS
webkit2gtk
fixed in 2.26.1-3
Ubuntu:20.04:LTS
wpewebkit
Ubuntu:22.04:LTS
qtwebkit-opensource-src
Ubuntu:22.04:LTS
wpewebkit
Ubuntu:24.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:16.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:16.04:LTS
qtwebkit-source
Ubuntu:Pro:16.04:LTS
webkit2gtk
Ubuntu:Pro:16.04:LTS
webkitgtk
Ubuntu:Pro:18.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:18.04:LTS
qtwebkit-source
Ubuntu:Pro:18.04:LTS
webkitgtk
⚠
Public Exploits & PoCs
3These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted.
📦
Fixed versions by distribution
39The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
alpine v3.19webkit2gtk fixed in 2.26.0-r0
alpine v3.20webkit2gtk fixed in 2.26.0-r0
rhel 8LibRaw open
rhel 8LibRaw-devel fixed in 0:0.19.5-2.el8
rhel 8gnome-settings-daemon fixed in 0:3.32.0-11.el8
rhel 8webkit2gtk3 fixed in 0:2.28.4-1.el8
rhel 8webkit2gtk3-devel open
rhel 8webkit2gtk3-jsc fixed in 0:2.28.4-1.el8
rhel 8webkit2gtk3-jsc-devel open
suse sle15WebKitGTK-4.0-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15WebKitGTK-4.1-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15WebKitGTK-6.0-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15libjavascriptcoregtk-4_0-18 fixed in 0:2.34.3-23.3
suse sle15libjavascriptcoregtk-4_1-0 fixed in 0:2.38.6-150400.4.39.1
suse sle15libjavascriptcoregtk-5_0-0 fixed in 0:2.36.0-150400.2.12
suse sle15libjavascriptcoregtk-6_0-1 fixed in 0:2.48.1-150600.12.36.5
suse sle15libwebkit2gtk-4_0-37 fixed in 0:2.34.3-23.3
suse sle15libwebkit2gtk-4_1-0 fixed in 0:2.48.1-150600.12.36.5
suse sle15libwebkit2gtk-5_0-0 fixed in 0:2.36.0-150400.2.12
suse sle15libwebkit2gtk3-lang fixed in 0:2.34.3-3.92.1
suse sle15libwebkitgtk-6_0-4 fixed in 0:2.48.1-150600.12.36.5
suse sle15typelib-1_0-JavaScriptCore-4_0 fixed in 0:2.34.3-3.92.1
suse sle15typelib-1_0-JavaScriptCore-4_1 fixed in 0:2.48.1-150600.12.36.5
suse sle15typelib-1_0-JavaScriptCore-5_0 fixed in 0:2.36.0-150400.2.12
suse sle15typelib-1_0-JavaScriptCore-6_0 fixed in 0:2.48.1-150600.12.36.5
suse sle15typelib-1_0-WebKit-6_0 fixed in 0:2.42.5-150600.10.36
suse sle15typelib-1_0-WebKit2-4_0 fixed in 0:2.34.3-23.3
suse sle15typelib-1_0-WebKit2-4_1 fixed in 0:2.36.0-150400.2.13
suse sle15typelib-1_0-WebKit2-5_0 fixed in 0:2.36.0-150400.2.12
suse sle15typelib-1_0-WebKit2WebExtension-4_0 fixed in 0:2.48.1-150600.12.36.5
suse sle15typelib-1_0-WebKit2WebExtension-4_1 fixed in 0:2.48.1-150600.12.36.5
suse sle15typelib-1_0-WebKitWebProcessExtension-6_0 fixed in 0:2.42.5-150600.10.36
suse sle15webkit2gtk-4_0-injected-bundles fixed in 0:2.34.3-23.3
suse sle15webkit2gtk-4_1-injected-bundles fixed in 0:2.42.5-150600.10.35
suse sle15webkit2gtk-5_0-injected-bundles fixed in 0:2.36.0-150400.2.12
suse sle15webkit2gtk3-devel fixed in 0:2.48.1-150600.12.36.5
suse sle15webkit2gtk3-soup2-devel fixed in 0:2.42.5-150600.10.35
suse sle15webkit2gtk4-devel fixed in 0:2.42.5-150600.10.36
suse sle15webkitgtk-6_0-injected-bundles fixed in 0:2.42.5-150600.10.36
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Scoring & Timeline
8.8
HIGH · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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Vendor Advisories
9suse-csafSUSE-SU-2022:0182-2
suse-csafopenSUSE-SU-2022:0182-1
suse-csafSUSE-SU-2022:0182-1
suse-csafSUSE-SU-2022:0183-1
🔗
References & Sources
2Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30761Third Party AdvisoryUS Government Resource