CVE-2026-15105 — davenardella snap7 ReadVar Request s7_server.cpp PerformFunctionRead out-of-bounds write
A flaw has been found in davenardella snap7 up to 1.4.3. This affects the function TS7Worker::PerformFunctionRead of the file src/core/s7_server.cpp of the component ReadVar Request Handler. This manipulation causes out-of-bounds write. The attack requires access to the local network. The exploit has been published and may be used. The project was informed of the problem early through an issue report but has not responded yet.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.4% (30-day exploitation probability)+5
- Technical severity (medium)+3
- CISA SSVC: exploitation "poc"+5
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.
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.
- Identify exposed assets running the affected vendor/product/version combinations (Davenardella Snap7).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- 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.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Davenardella | Snap7 | version 1.4.0version 1.4.1version 1.4.2version 1.4.3 | Vulnerable | CVE Program (cve.org) e CISA ADP |
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.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.3 | CVSS 4.0 | Medium | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 2.1 | CVSS 4.0 | Low | — | — | cna@vuldb.com via NIST National Vulnerability Database |
| 6.3 | CVSS 3.1 | Medium | 2.8 | 3.4 | cna@vuldb.com via NIST National Vulnerability Database |
| 6.3 | CVSS 3.1 | Medium | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 6.3 | CVSS 3.0 | Medium | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 5.8 | CVSS 2.0 | Medium | 6.5 | 6.4 | cna@vuldb.com via NIST National Vulnerability Database |
| 5.8 | CVSS 2.0 | Medium | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L (score shown at the top: cna@vuldb.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · davenardella/snap7
- SSVC assessment updated
- Record published
- CVSS changed · 6.3
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
7 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-111280 snap7 through 1.4.3 Out-of-Bounds Write via TSnap7MicroClient::opReadArea 6h
- Medium CVE-2026-90572 davenardella snap7 s7_micro_client.cpp opUpload memory corruption Sep 13, 2026
- Medium CVE-2026-16225 davenardella snap7 s7_peer.cpp NegotiatePDULength out-of-bounds write Jul 19, 2026
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-2026-15105 is "davenardella snap7 ReadVar Request s7_server.cpp PerformFunctionRead out-of-bounds write", rated Medium. It affects Snap7 (Davenardella); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.3 describes technical severity. EPSS 0.38% 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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