What is CVE-2026-61741?

CVE-2026-61741 is http4s-scala-xml has an XML External Entity (XXE) processing issue. The supplied enrichment data classifies it as Injection mapped to CWE-611 XML External Entity Reference.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-61741. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-61741 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-61741. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, database audit logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-61741 using CVSS 9.3, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

criticalInjection

CVE-2026-61741

CVE-2026-61741 — http4s-scala-xml has an XML External Entity (XXE) processing issue

http4s-scala-xml provides `EntityDecoder[F, scala.xml.Elem]` instances that parse XML message bodies. Prior to versions 0.24.1 and 1.0.0-M39, these decoders used a `javax.xml.parsers.SAXParserFactory` obtained from `SAXParserFactory.newInstance` without any security configuration. With the JDK's default settings, the parser resolves DOCTYPE declarations, external general and parameter entities, and external DTDs.An application that uses these decoders to parse untrusted XML is vulnerable to XML External Entity (XXE) attacks. An attacker can craft a request that discloses local files readable by the service process, performs server-side request forgery (SSRF) against internal network resources, and/or causes denial of service through entity expansion. Versions 0.24.1 and 1.0.0-M39 fix the issue.

Published Sep 24, 2026Updated Sep 24, 2026Sources: NVD, http4s (CNA), GitHub

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

Not scored

FIRST has not published a score

Affects

http4s

2 products listed

CVSS base

9.3

critical

Remediation

The vendor's own words where we have them.

Upgrade http4s-scala-xml to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
http4s	http4s-scala-xml	< 0.24.1	Vulnerable
http4s	http4s-scala-xml	>= 1.0.0-M1, < 1.0.0-M39	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

Low

Confidentiality

High

Integrity

None

Scope

Changed

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.3	CVSS 3.1	critical	3.9	4.7	GitHub (CNA), http4s (CNA)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L

Weakness & attack patterns

CWE-611XML External Entity Reference

Inferred from the weakness class — not observed against this CVE.

CAPEC-66 · SQL InjectionCAPEC-7 · Blind SQL Injection

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /or.
Prioritize edge telemetry for network-reachable http4s-scala-xml.

web/proxy/WAF logsapplication logsnetwork IDS/IPSdatabase audit logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 9.3 (AV:N)
Sep 24, 2026 · NVD
Initial · CVE published
Sep 24, 2026 · NVD

References

1 on the record

github.com/http4s/http4s-scala-xml/security/advisories/GHSA-cjx3-73hr-rpw7
Exploit, Third Party Advisory

Elsewhere on this site

http4severy CVE for this vendor
Injectionsame class
CWE-611other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-61741 is http4s-scala-xml has an XML External Entity (XXE) processing issue, a critical vulnerability affecting http4s-scala-xml from http4s. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-61741. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-61741. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.3 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.