CVE Intelligence
Medium Memory corruption

CVE-2025-41739 — CODESYS Control - Linux/QNX SysSocket flaw

An unauthenticated remote attacker, who beats a race condition, can exploit a flaw in the communication servers of the CODESYS Control runtime system on Linux and QNX to trigger an out-of-bounds read via crafted socket communication, potentially causing a denial of service.

Published Dec 1, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: CERTVDE

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+4
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

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

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.35%
ahead of 26% of scored CVEs · Oct 14, 2026
Affects
CODESYS
CODESYS Edge Gateway for Linux and 15 more
CVSS base
5.9
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (CODESYS CODESYS Edge Gateway for Linux, CODESYS CODESYS PLCHandler, CODESYS CODESYS TargetVisu for Linux SL…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
CODESYS CODESYS Edge Gateway for Linux ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS CODESYS PLCHandler ≥ 3.5.21.0 and < 3.5.21.40 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS CODESYS TargetVisu for Linux SL ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Beaglebone Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Empc-a/imx6 Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Iot2000 Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Linux Arm Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Linux Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Pfc100 Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Pfc200 Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Plcnext Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Raspberry Pi Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Control For Wago Touch Panels 600 Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Remote Target Visu ≥ 3.5.21.0 and < 3.5.21.40 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Runtime Toolkit ≥ 3.5.21.0 and < 3.5.21.40 Vulnerable CVE Program (cve.org) e CISA ADP
CODESYS Virtual Control Sl ≥ 4.15.0.0 and < 4.19.0.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

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

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
5.9 CVSS 3.1 Medium 2.2 3.6 info@cert.vde.com via NIST National Vulnerability Database
5.9 CVSS 3.1 Medium — — CERTVDE via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: info@cert.vde.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-125 · Out-of-bounds Read

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.35%

Detection

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

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · codesys/codesys plchandler, codesys/codesys remote target visu, codesys/codesys runtime toolkit, codesys/codesys control
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 5.9
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2025
  • CVE published
    Dec 1, 2025 · CERTVDE

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

CODESYS
every CVE for this vendor
Memory corruption
same class
CWE-125
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-8046 Incorrect Authorization in CODESYS Control May 26, 2026
  • CVE-2026-8047 Out-of-bounds Write in CODESYS Control May 26, 2026
  • CVE-2026-3509 CODESYS Control Audit Log Format String DoS Mar 24, 2026
  • CVE-2025-41660 CODESYS Control Boot Application Replacement Enables Code Execution Mar 24, 2026
  • CVE-2025-41738 CODESYS Control - Invalid type usage in visualization Dec 1, 2025

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 fixed version, patch or mitigation documented.
  • 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 record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-41739 is "CODESYS Control - Linux/QNX SysSocket flaw", rated Medium. It affects CODESYS Edge Gateway for Linux (CODESYS); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. EPSS 0.35% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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