CVE-2026-27830

HIGHCVSS 8.08.0Trending — 4 sources updated this week

Also known asEUVD-2026-8786 (ENISA EUVD) · GHSA-5476-xc4j-rqcv (GitHub Security Advisories)Source: ENISA EUVD

8.0EG

EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).

High severity, but no confirmed exploitation yet

CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.0Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

c3p0, a JDBC Connection pooling library, is vulnerable to attack via maliciously crafted Java-serialized objects and javax.naming.Reference instances. Several c3p0 ConnectionPoolDataSource implementations have a property called userOverridesAsString which conceptually represents a Map>. Prior to v0.12.0, that property was maintained as a hex-encoded serialized object. Any attacker able to reset this property, on an existing ConnectionPoolDataSource or via maliciously crafted serialized objects or javax.naming.Reference instances could be tailored execute unexpected code on the application's CLASSPATH. The danger of this vulnerability was strongly magnified by vulnerabilities in c3p0's main dependency, mchange-commons-java. This library includes code that mirrors early implementations of JNDI functionality, including ungated support for remote factoryClassLocation values. Attackers could set c3p0's userOverridesAsString hex-encoded serialized objects that include objects "indirectly serialized" via JNDI references. Deserialization of those objects and dereferencing of the embedded javax.naming.Reference objects could provoke download and execution of malicious code from a remote factoryClassLocation. Although hazard presented by c3p0's vulnerabilites are exarcerbated by vulnerabilities in mchange-commons-java, use of Java-serialized-object hex as the format for a writable Java-Bean property, of objects that may be exposed across JNDI interfaces, represents a serious independent fragility. The userOverridesAsString property of c3p0 ConnectionPoolDataSource classes has been reimplemented to use a safe CSV-based format, rather than rely upon potentially dangerous Java object deserialization. c3p0-0.12.0+ and above depend upon mchange-commons-java 0.4.0+, which gates support for remote factoryClassLocation values by configuration parameters that default to restrictive values. c3p0 additionally enforces the new mchange-commons-java com.mchange.v2.naming.nameGuardClassName to prevent injection of unexpected, potentially remote JNDI names. There is no supported workaround for versions of c3p0 prior to 0.12.0.

CVSS v3: 8.0
EG Score: 8.0HIGHmedium confidence
EG Risk: 36
EPSS PROB: 0.6%
EPSS %ILE: 48th
KEV: Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (8.0): severity, escalated by confirmed exploitation. This CVE's 8.0 is its impact severity (EG Severity), not escalated.

EG Severity: 8.0 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood: 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation: None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority: SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (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

Published

February 26, 2026

Last Modified

September 15, 2026