CVE-2026-54617VulnerabilityPublished 2 Jul 2026

Pro.gravit.launcher:launchserver api: LaunchServer FileServerHandler has an unauthenticated path traversal issue

Affects pro.gravit.launcher:launchserver-apiSource GCVE Database

Authoritative record:CVE-2026-54617· Critical 9.8

Not known to be exploited · public detection template (Nuclei) · CVSS 9.8 Critical · fixed in 5.7.12 : patch pro.gravit.launcher:launchserver-api as a priority.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 3.4% chance of exploitation in 30 days – higher than 89% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.7.12

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: evidence found.
nuclei template: GravitLauncher LaunchServer <=5.7.11 - Unauthenticated Path Traversal to Arbitrary File Read
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Mavenpro.gravit.launcher:launchserver-api	Affected <=5.7.11	Fixed in–

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Description

### Summary An unauthenticated path traversal in the LaunchServer HTTP file server (`FileServerHandler`) lets any remote actor read **any file** readable by the LaunchServer process (e.g. `../../../../etc/passwd`). This is a generic arbitrary-file-read primitive, so the fix must address the traversal itself, not any specific file. The readable files include the server's own secrets, which turns this from information disclosure into full compromise: the ECDSA private key that signs access JWTs (`.keys/ecdsa_id`), the refresh-token salt (`.keys/legacySalt`), and `LaunchServer.json` (database credentials). With the signing key an attacker mints a valid access token for any account, including admins. That is a full authentication bypass. Pre-auth, default config, port 9274. **Affected:** GravitLauncher LaunchServer ≤ 5.7.11 (the LaunchServer application; the published `pro.gravit.launcher:*-api` Maven artifacts do not contain the vulnerable code). ### Details In `FileServerHandler.channelRead0`: ```java path = Paths.get(IOHelper.getPathFromUrlFragment(uri)).normalize().toString().substring(1); // line 194 File file = base.resolve(path).toFile(); // line 200 - no second normalize() ``` `substring(1)` blindly strips a leading slash, assuming the request-target always starts with `/`. Netty's `HttpServerCodec` accepts a request-target **without** a leading slash verbatim (`decoderResult().isSuccess() == true`). For such a target, `normalize()` cannot collapse the leading `..`, `substring(1)` turns `../` into `./` (leaving the remaining `..`), and `base.resolve(path)`, which is not re-normalized, resolves **outside** `updatesDir`. `file.isHidden()` (line 201) is checked only on the final path component, so targets that don't start with a dot (`ecdsa_id`, `rsa_id`, `legacySalt`, `LaunchServer.json`) are served even with `showHiddenFiles=false`. The file server is enabled by default (`netty.fileServerEnabled=true`) and bound to `0.0.0.0:9274`. No auth handler precedes `FileServerHandler`; `WebSocketServerProtocolHandler("/api")` forwards non-WebSocket / non-`/api` requests down to it, so the attack is a plain HTTP GET (no WebSocket). ### PoC Reproduced on a from-source build of v5.7.11 (Netty 4.2.12). **Must use a raw socket.** curl/browsers/HTTP libraries normalize the path and prepend `/`, hitting the safe branch (false "not reproducible"). ``` printf 'GET ../../.keys/ecdsa_id HTTP/1.1\r\nHost: x\r\n\r\n' | nc <host> 9274 ``` Returns the raw ECDSA private-key bytes. Same for `../../.keys/rsa_id`, `../../.keys/legacySalt`, `../../LaunchServer.json`. `%2e%2e/...` (no leading slash) also works. Depth-robust arbitrary read: `../../../../../../etc/passwd`. Control (confirms the root cause): `GET /../../.keys/ecdsa_id` (WITH leading slash) → 404. Only the no-leading-slash form escapes. ### Impact Unauthenticated remote read of any file the process can access. What that exposes: - `.keys/ecdsa_id`: the key that signs access JWTs. With it, an attacker mints a valid token for any account, including admins, so this is a full authentication bypass. - `.keys/legacySalt`: lets an attacker forge refresh tokens. - `LaunchServer.json`: database credentials. - Any other file readable by the process (config, logs, system files). Deployment note: a normalizing L7 reverse proxy (stock nginx `location / { proxy_pass ...; }`) rejects the no-leading-slash request (400) and collapses leading-slash traversal, blocking the primary vector. But the default bind is `0.0.0.0:9274`, so protection relies on firewalling the backend port; L4/TCP proxies (HAProxy TCP, nginx `stream`, CF Spectrum) and direct exposure remain exploitable. ### Suggested fix 1. Re-`normalize()` after `base.resolve(path)` and verify `resolved.startsWith(base)`. 2. Reject request-targets that don't start with `/` (400). 3. Default-bind to `127.0.0.1`; store `.keys` outside `updatesDir`.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-22Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-522Insufficiently Protected Credentials (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
Architecture and Design
Use an appropriate security mechanism to protect the credentials.
Architecture and Design
Make appropriate use of cryptography to protect the credentials.
Implementation
Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V2.10.3 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
Attack patterns
Session Sidejacking (opens in a new tab)
Signature Spoofing by Key Theft (opens in a new tab)
Password Recovery Exploitation (opens in a new tab)
Kerberoasting (opens in a new tab)
Modify Existing Service (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

Public exploits and detectiona Nuclei detection template

WeaknessesCWE-200, CWE-22, CWE-522

Technical details

References

Community reviews

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