CVE-2026-3909: Qtwebkit opensource src · security update
Affects Google qtwebkit-opensource-srcSource GCVE Database
Exploited in the wild · KEV due 27 Mar 2026 · 2% EPSS : apply the vendor's fix or mitigations to Google qtwebkit-opensource-src now.
Data as of 28 Oct 2026, 05:11 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- EPSS
- 2.3% chance of exploitation in 30 days – higher than 83% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 12 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 1 day after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by Chrome
, 45 hours before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 14 minutes after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed
, 1 day after disclosure
KEV remediation due
US federal deadline
, 15 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10webkit2gtkpkg:deb/ubuntu/webkit2gtk?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSwebkit2gtkpkg:deb/ubuntu/webkit2gtk?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSqtwebkit-opensource-srcpkg:deb/ubuntu/qtwebkit-opensource-src?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSwebkit2gtkpkg:deb/ubuntu/webkit2gtk?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSqtwebkit-opensource-srcpkg:deb/ubuntu/qtwebkit-opensource-src?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSwebkit2gtkpkg:deb/ubuntu/webkit2gtk?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
CVE-2026-3909 is a high severity security vulnerability affecting multiple specific versions of the QtWebKit open source component. It has a CVSS 3.1 base score of 8.8, indicating a critical impact on confidentiality, integrity, and availability. The vulnerability requires no privileges and can be exploited remotely with user interaction. A security update has been issued to address this flaw.