An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.
CVE-2021-30952
“▲” beside the score: it is higher than NVD's CVSS score.
Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-03-05), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.8 retained for reference. The 9.0 is the floor for confirmed exploitation, not an impact rating: this CVE's impact severity (EG Severity) is CVSS 7.8 HIGH under NVD CVSS v3. Confidence: HIGH.
- Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low or medium mission impact
A fix is available — apply it.
- CVSS v3
- 7.8
- EG Score
- 9.0CRITICALhigh confidence
- EG Risk
- 75EG Risk 75/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity78% × 45%Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation100% × 40%Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Attend at medium and Act at high mission impact.Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact. - EPSS PROB
- 7.0%
- EPSS %ILE
- 94th
- KEV
- ⚠ Exploited
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is the CISA KEV floor for confirmed exploitation, not an impact rating: its impact severity (EG Severity) is CVSS 7.8 HIGH.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 7.0% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Attend at medium mission impactTrack at low, Attend at medium and Act at high mission impact.CISA BOD 26-04: 3 days & forensic triage if the affected system is publicly exposed; 14 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Attend at medium and Act at high mission impact.
A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.
Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days & forensic triage if the affected system is publicly exposed; 14 days if it is not.
In CISA KEV yes (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
CISA required action“Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”
Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://support.apple.com/en-us/HT212975 · https://support.apple.com/en-us/HT212976 · https://support.apple.com/en-us/HT212978 · https://support.apple.com/en-us/HT212980 · https://support.apple.com/en-us/HT212982 · https://nvd.nist.gov/vuln/detail/CVE-2021-30952
Published
August 24, 2021
Last Modified
March 6, 2026
Advisory Details (10)
Auto-updated Oct 19, 2026[SECURITY] [DSA 5061-1] wpewebkit security update
https://www.debian.org/security/2022/dsa-5061[SECURITY] [DSA 5060-1] webkit2gtk security update
https://www.debian.org/security/2022/dsa-5060About the security content of Safari 15.2 - Apple Support
https://support.apple.com/en-us/HT212982About the security content of tvOS 15.2 - Apple Support
https://support.apple.com/en-us/HT212980About the security content of macOS Monterey 12.1 - Apple Support
https://support.apple.com/en-us/HT212978About the security content of iOS 15.2 and iPadOS 15.2 - Apple Support
https://support.apple.com/en-us/HT212976About the security content of watchOS 8.3 - Apple Support
https://support.apple.com/en-us/HT212975[SECURITY] Fedora 34 Update: webkit2gtk3-2.34.4-1.fc34 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HQKWD4BXRDD2YGR5AVU7H5J5PIQIEU6V/[SECURITY] Fedora 35 Update: webkit2gtk3-2.34.4-2.fc35 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7EQVZ3CEMTINLBZ7PBC7WRXVEVCRHNSM/oss-security - WebKitGTK and WPE WebKit Security Advisory WSA-2022-0001
http://www.openwall.com/lists/oss-security/2022/01/21/2Vendor Advisories for CVE-2021-30952(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(3)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libwebkit2gtk-4.0-dev (2.34.4-0ubuntu0.21.10.1) @ impish | 2026-10-21 | ubuntu |
| redhat | webkitgtk4-0:2.48.3-2.el7_9 | 2025-07-07 | redhat |
| redhat | webkit2gtk3-0:2.34.6-1.el8 | 2022-05-10 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(9 across 5 ecosystems)
Debian:11(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| webkit2gtk | 2.32.3-1 ... 2.34.4-1~deb10u1 (20 versions) |
| — |
| wpewebkit | 2.32.3-2 ... 2.34.3-1~deb11u1 (8 versions) |
| — |
Debian:12(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| webkit2gtk | — |
| — |
| wpewebkit | — |
| — |
Debian:13(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| webkit2gtk | — |
| — |
| wpewebkit | — |
| — |
Debian:14(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| webkit2gtk | — |
| — |
| wpewebkit | — |
| — |
Debian:10(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| webkit2gtk | 2.24.2-1 ... 2.34.3-1~deb11u1 (105 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(2)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 21× in last 7d / 200× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 1,194 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 1,094 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-23 08:14 UTCEG score recompute
- 2026-10-23 08:14 UTCVendor advisory
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-22 10:06 UTCEG score recompute
- 2026-10-22 10:06 UTCVendor advisory
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-21 11:55 UTCEG score recompute
- 2026-10-21 11:55 UTCVendor advisory
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-20 13:47 UTCEG score recompute
- 2026-10-20 13:47 UTCVendor advisory
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-19 15:37 UTCVendor advisory
- 2026-10-18 17:28 UTCEG score recompute
- 2026-10-18 17:28 UTCVendor advisory
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-18 09:02 UTCEG score recompute
- 2026-10-17 19:20 UTCEG score recompute
- 2026-10-17 19:20 UTCVendor advisory
- 2026-10-17 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-16 21:11 UTCEG score recompute
- 2026-10-16 21:11 UTCVendor advisory
- 2026-10-16 16:33 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-15 23:01 UTCEG score recompute
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- 2026-10-15 23:01 UTCVendor advisory
- 2026-10-15 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-15 00:54 UTCEG score recompute
- 2026-10-15 00:54 UTCVendor advisory
- 2026-10-14 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-14 02:45 UTCEG score recompute
- 2026-10-14 02:45 UTCVendor advisory
- 2026-10-13 16:28 UTCEPSS rescoreEPSS 7.0% · 94th percentile
- 2026-10-13 04:36 UTCVendor advisory
- 2026-10-12 19:17 UTCEG score recompute
- 2026-10-12 16:29 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-12 06:27 UTCVendor advisory
- 2026-10-12 02:38 UTCVendor advisory
- 2026-10-11 22:53 UTCEG score recompute
- 2026-10-11 22:53 UTCVendor advisory
- 2026-10-11 19:06 UTCEG score recompute
- 2026-10-11 19:06 UTCVendor advisory
- 2026-10-11 15:20 UTCEG score recompute
- 2026-10-11 15:20 UTCVendor advisory
- 2026-10-11 13:43 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-11 11:35 UTCEG score recompute
- 2026-10-11 11:35 UTCVendor advisory
- 2026-10-11 07:51 UTCVendor advisory
- 2026-10-11 04:05 UTCVendor advisory
- 2026-10-11 00:20 UTCVendor advisory
- 2026-10-10 20:35 UTCEG score recompute
- 2026-10-10 20:35 UTCVendor advisory
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-10 16:49 UTCVendor advisory
- 2026-10-10 13:02 UTCVendor advisory
- 2026-10-10 09:18 UTCVendor advisory
- 2026-10-10 05:33 UTCVendor advisory
- 2026-10-10 01:48 UTCVendor advisory
- 2026-10-09 22:03 UTCEG score recompute
- 2026-10-09 22:03 UTCVendor advisory
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-09 18:17 UTCVendor advisory
- 2026-10-09 14:32 UTCVendor advisory
- 2026-10-09 10:42 UTCVendor advisory
- 2026-10-09 06:54 UTCVendor advisory
- 2026-10-09 03:10 UTCVendor advisory
- 2026-10-08 23:25 UTCVendor advisory
- 2026-10-08 19:40 UTCEG score recompute
- 2026-10-08 19:40 UTCVendor advisory
- 2026-10-08 16:39 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-08 15:55 UTCVendor advisory
- 2026-10-08 12:10 UTCVendor advisory
- 2026-10-08 08:25 UTCVendor advisory
- 2026-10-08 04:40 UTCVendor advisory
- 2026-10-08 00:56 UTCEG score recompute
- 2026-10-08 00:56 UTCVendor advisory
- 2026-10-07 23:44 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-07 21:11 UTCVendor advisory
- 2026-10-07 17:26 UTCVendor advisory
- 2026-10-07 13:40 UTCVendor advisory
- 2026-10-07 09:54 UTCVendor advisory
- 2026-10-07 06:09 UTCVendor advisory
- 2026-10-07 02:24 UTCVendor advisory
- 2026-10-06 22:39 UTCVendor advisory
- 2026-10-06 18:54 UTCEG score recompute
- 2026-10-06 18:54 UTCVendor advisory
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-06 15:10 UTCVendor advisory
- 2026-10-06 11:24 UTCVendor advisory
- 2026-10-06 07:39 UTCVendor advisory
- 2026-10-06 03:55 UTCVendor advisory
- 2026-10-06 00:08 UTCVendor advisory
- 2026-10-05 20:23 UTCEG score recompute
- 2026-10-05 20:23 UTCVendor advisory
- 2026-10-05 17:40 UTCEPSS rescoreEPSS 7.0% · 93rd percentile
- 2026-10-05 16:38 UTCVendor advisory
- 2026-10-05 12:54 UTCVendor advisory
- 2026-10-05 09:09 UTCVendor advisory
- 2026-10-05 05:22 UTCVendor advisory
- 2026-10-05 01:37 UTCEG score recompute
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:10:webkit2gtk
- CVE-2020-13753EG 10.0CRITICAL
- CVE-2023-25363NVD 8.8EG 9.8CRITICAL
- CVE-2023-25362NVD 8.8EG 9.8CRITICAL
- CVE-2023-25361NVD 8.8EG 9.8CRITICAL
- CVE-2023-25360NVD 8.8EG 9.8CRITICAL
- CVE-2023-25358NVD 8.8EG 9.8CRITICAL
- CVE-2021-1871EG 9.8 KEVEPSS p94CRITICAL
- CVE-2021-1870EG 9.8 KEVEPSS p95CRITICAL
- CVE-2020-9895EG 9.8EPSS p91CRITICAL
- CVE-2020-9850EG 9.8EPSS p100CRITICAL
Same vendor
10 shownredhat:RHSA-2022:1777 · redhat:RHSA-2025:10364
Frequently asked(6)
What is CVE-2021-30952?
When was the CVE record for CVE-2021-30952 published?
Is CVE-2021-30952 actively exploited?
What is the CVSS score of CVE-2021-30952?
Which products are affected by CVE-2021-30952?
How do I remediate CVE-2021-30952?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-30952
Is Your Infrastructure Affected by CVE-2021-30952?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.