CVE-2026-78381 — RansomLook Arbitrary File Read via Path Traversal in Post screen Field
RansomLook contains a path traversal vulnerability in the handling of the screen field associated with group posts. The GroupPost.get API handler concatenates the database-controlled screen value directly with the application's source/ directory and opens the resulting path without verifying that the resolved file remains within the intended directory. Because the screen field is free-form and can be populated either through the administrative post editor or through data imported from a remote RansomLook instance, a malicious upstream instance can provide traversal sequences such as ../config/generic.json. When the affected post is subsequently retrieved through the API, RansomLook resolves and reads the attacker-controlled path and returns the contents of the referenced file Base64-encoded in the API response. This can allow an attacker (being admin) controlling imported post data to read arbitrary files accessible to the RansomLook process, potentially exposing sensitive configuration data, API credentials, password hashes, or other application secrets. The attack does not require the malicious upstream to possess an account on the affected RansomLook instance. The vulnerability is addressed by resolving screen paths with os.path.realpath() and verifying that the resolved path remains beneath the application's source/ directory. Validation is performed both when values are written and immediately before files are read. Using canonical paths also prevents traversal through symbolic links that would bypass purely lexical path normalization checks.
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 0.6% (30-day exploitation probability)+7
- Technical severity (high)+6
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 (Ransomlook Ransomlook).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Ransomlook | Ransomlook | ≤ 2.0.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
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 |
|---|---|---|---|---|---|
| 8.2 | CVSS 4.0 | High | — | — | 5a6e4751-2f3f-4070-9419-94fb35b644e8 via NIST National Vulnerability Database |
| 8.2 | CVSS 4.0 | High | — | — | CIRCL via CVE Program (cve.org) e CISA ADP |
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: 5a6e4751-2f3f-4070-9419-94fb35b644e8) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.59%
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).
- Monitor file creation in web directories and paths with traversal sequences (../).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · ransomlook/ransomlook
- SSVC assessment updated
- Record published
- CVSS changed · 8.2
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
3 on the record
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-78555 RansomLook API Key Disclosure Through /admin/apikeys HTML Source Aug 24, 2026
- High CVE-2026-78553 Insecure Flask Secret-Key File Permissions Allow Local Administrator Session Forgery in RansomLook Aug 24, 2026
- High CVE-2026-78551 RansomLook Login Endpoint Allows Timing-Based Username Enumeration and Unthrottled Authentication Attempts Aug 24, 2026
- Critical CVE-2026-78387 RansomLook Missing Authorization in Web Configuration Editor Allows Application Configuration Modification Aug 24, 2026
- High CVE-2026-78391 Stored Cross-Site Scripting via Untrusted Cryptocurrency Address Rendering in RansomLook Aug 24, 2026
- High CVE-2026-78386 Unauthenticated Disclosure of Scraping Credentials and Bypass Configuration via RansomLook API Aug 24, 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-2026-78381 is "RansomLook Arbitrary File Read via Path Traversal in Post screen Field", rated High. It affects Ransomlook (Ransomlook); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.2 describes technical severity. EPSS 0.59% 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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