CVE-2024-49849 — Deserialization of Untrusted Data in Siemens SIMATIC S7-PLCSIM V16

Triage

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

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.

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 (Siemens SIMATIC S7-PLCSIM V16, Siemens SIMATIC S7-PLCSIM V17, Siemens SIMATIC STEP 7 Safety V16…).
2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
3. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
4. Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

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

Every base score collected

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

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-502 · Deserialization of Untrusted Data

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.22%

Detection

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

• Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
• Monitor serialized objects in requests and unexpected processes spawned by the runtime.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products removed · 6
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Affected products added · siemens/simatic step 7 safety v18, siemens/simatic step 7 v18, siemens/simatic wincc unified v18, siemens/simatic wincc
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Affected products removed · 6
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Affected products added · siemens/simatic step 7 safety v18, siemens/simatic step 7 v18, siemens/simatic wincc unified v18, siemens/simatic wincc
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Affected products added · siemens/simatic s7-plcsim v16, siemens/simatic s7-plcsim v17, siemens/simatic step 7 safety v16, siemens/simatic step 7
  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 · 7.8
  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
• 2024
• CVE published
  Dec 10, 2024 · siemens

Source activity

Repeated readings are counted rather than listed.

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

References

1 on the record

• cert-portal.siemens.com/productcert/html/ssa-800126.html
  NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2025-40759 Deserialization of Untrusted Data in Siemens SIMATIC S7-PLCSIM V17 Aug 12, 2025
• High CVE-2024-54678 Deserialization of Untrusted Data in Siemens SIMATIC PCS neo V4.1 Aug 12, 2025
• High CVE-2025-30033 Uncontrolled Search Path Element in Siemens Automation License Manager V6.0 Aug 12, 2025
• High CVE-2024-52051 Improper Input Validation in Siemens SIMATIC S7-PLCSIM V17 Dec 10, 2024

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-2024-49849 is "Deserialization of Untrusted Data in Siemens SIMATIC S7-PLCSIM V16", rated High. It affects SIMATIC S7-PLCSIM V16 (Siemens); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.22% 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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