CVE-2025-5455 | Possible denial of service when passing malformed data in a URL to qDecodeDataUrl

An issue was found in the private API function qDecodeDataUrl() in QtCore, which is used in QTextDocument and QNetworkReply, and, potentially, in user code. If the function was called with malformed data, for example, an URL that contained a "charset" parameter that lacked a value (such as "data:charset,"), and Qt was built with assertions enabled, then it would hit an assertion, resulting in a denial of service (abort). This impacts Qt up to 5.15.18, 6.0.0->6.5.8, 6.6.0->6.8.3 and 6.9.0. This has been fixed in 5.15.19, 6.5.9, 6.8.4 and 6.9.1.

Published: 2025-06-02 Last update: 2026-04-15 Assigner: a59d8014-47c4-4630-ab43-e1b13cbe58e3 Source: a59d8014-47c4-4630-ab43-e1b13cbe58e3
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-5455 is rated Moderate Risk (54.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.39%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-5455

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-29 0.12% 0.39% +0.27%
2 2025-11-21 0.18% 0.12% -0.07%
3 2025-11-18 — 0.18% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-5455

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.4 4.0 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:X/RE:M/U:Clear Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:A)
User interaction is required in an active way.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:H)
High integrity impact on subsequent systems.
Subsequent system availability impact (SA:H)
High availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:U)
User: manual user intervention is needed to recover services.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:M)
Moderate effort (remote update, disable subsystem, simple upgrade with minor service impact).
Provider urgency (supplemental) (U:CLEAR)
Clear: provider rates this as informational urgency.
 — — a59d8014-47c4-4630-ab43-e1b13cbe58e3

Weakness enumeration for CVE-2025-5455

OS Trackers for CVE-2025-5455

vendor priority summary link
debian unimportant CVE-2025-5455 unimportant priority: Debian including 3 source packages (qt6-base, qtbase-opensource-src, qtbase-opensource-src-gles), 14 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11, open 3. https://security-tracker.debian.org/tracker/CVE-2025-5455
redhat medium — https://access.redhat.com/security/cve/CVE-2025-5455
suse medium CVE-2025-5455 severity moderate: SUSE including 494 source package names (0.6.18-12.30:libQt5Core5-5.15.12+kde151-150600.3.9.1, 0.6.18-12.30:libQt5DBus5-5.15.12+kde151-150600.3.9.1, …), 903 product×package rows across 51 product lines (Container containers/open-webui, Container containers/vllm-openai, … (51 product lines)): Fixed 641, Known Affected 231, Known Not Affected 31. https://www.suse.com/security/cve/CVE-2025-5455/
ubuntu medium CVE-2025-5455 medium priority: Ubuntu including 3 source packages (qt6-base, qtbase-opensource-src, qtbase-opensource-src-gles), 24 status rows across 9 suites (bionic, focal, jammy, noble, oracular, plucky, questing, upstream, xenial): ignored 11, needs-triage 10, DNE 1, not-affected 1, released 1. https://ubuntu.com/security/CVE-2025-5455

Affected software / configurations for CVE-2025-5455

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-5455

cvelogic Threat Intelligence