Signal K resources API traversal (CVE-2026-123807)

A caller can escape the configured resource directory through an affected Signal K REST resource identifier. Upgrade Signal K Server and the affected provider to protect files outside the resource store.

Public CVE record · Source and API bundle

cve.now entry.

Eden terminates the HTTP connection to the affected product, evaluates a declarative policy and — in tier 2 — a separately compiled native Rust module under signed module authority, before any byte reaches the application. It does not patch the affected component; the vendor's fixed release remains the durable repair.

Status: live two-tier remediation recorded (blocklist; partiality stated) 2026-11-11 on the installed eden-product-release:1.103.0-single lab container (image sha256:809293e1f0b525ac04698d1fa8d7ffdc66cbee1ff690b082ba26b4d050f08416).

The vulnerability

The v2 resources API path traversal reads arbitrary JSON including security settings exposing the token-signing secret, enabling admin token forgery and command execution.

The Eden patch

Tier 1 — declarative policy (blunt, fail-closed): deny on the affected route family — takes the whole surface offline, legitimate calls included.

Tier 2 — native module: gabriel_signalk_v1, binary SHA-256 8085bddfc069b1436b1bb5b6db15f68b03a4a7846f94e18ae232345c20cb08ce (source db2ac5746c094214b31e9ba5ee94bb1ffd03c1062fad04b67f2352649f9c2ed2) — refuse traversal bytes (plain and encoded) in resources queries.

Implement the remediation

The commands are operator examples for the recorded scope. Compare fixture routes and software selectors with the intended deployment before use. See deployment prerequisites.

1. Prepare the target. Verify the loaded product and version against the advisory. Use a compatible Eden HTTP interlay and an authenticated operator with Configure permission. Open the deployment example and API instructions. The bundle identifies module gabriel_signalk_v1 version 1.0.0 and the SDK revision in patch.toml. Run the policy extraction from the adapter directory.
2. Apply the declarative policy. Scope the policy to /signalk/v1/resources and descendants (all methods, deny). Set INTERLAY to the target interlay UUID in the authenticated Eden CLI. Run an authenticated GET /api/v1/interlays/{interlay} with X-Eden-Verbose: true. Save its complete current settings object as current-settings.json and retain the prior remediation declaration for recovery. Set IDEMPOTENCY_KEY to a fresh key for this intended mutation.

jq -e '.tier1' deployment.json > remediation.json
jq -e --slurpfile policy remediation.json \
  '.remediation = $policy[0] | {settings: .}' current-settings.json \
  > interlay-update.json
eden api request PATCH "/api/v1/interlays/$INTERLAY" \
  --header "Idempotency-Key:$IDEMPOTENCY_KEY" \
  --body-file interlay-update.json --content-type application/json --confirm

3. Verify the serving policy. Read back the interlay.

eden api request GET "/api/v1/interlays/$INTERLAY" \
  --header 'X-Eden-Verbose:true'

Check that remediation_status.state is ready and both desired and effective SHA-256 values match the intended declaration. Replay the benign and marked requests in the recorded comparison on an isolated target. Check the recorded response and backend outcome for each probe. Use the request and expected-status table in the linked API example alongside the observed comparison. 4. Restore the previous policy. Coordinate the change with any other operator updating this interlay. Read current settings again and merge the saved remediation field into them. If the prior settings had no remediation field, omit it in the replacement. Send the same PATCH with a fresh idempotency key, then read back the intended state. Repeat the verification probes. Keep the affected route isolated if restoring the prior settings reopens exposure.

Native module gabriel_signalk_v1

1. Prepare the archive. Use the version 1.0.0 bundle for source, target, and build profile. Configure independent host approval for the installed Eden release. Use the authenticated principals required by the native authority contract. Set PATCH_ARCHIVE to the exact schema-2 package and PACKAGE_SHA256 to its expected archive digest. Verify and import it using the same target interlay.

printf '%s  %s\n' "$PACKAGE_SHA256" "$PATCH_ARCHIVE" | sha256sum --check &&
  eden api request PUT "/api/v1/interlays/$INTERLAY/patch-packages/$PACKAGE_SHA256" \
    --body-file "$PATCH_ARCHIVE" \
    --content-type application/vnd.eden.patch-package.v2+tar --confirm

2. Approve and activate. Enroll the publisher key, attest host software inventory, and inspect the configuration returned by import. Obtain independent host approval. Sign the typed statement with the matching SDK. Send the admit action followed by activate for the prepared operation. Use the applicable typed payload for each action in authority-action.json.

eden api request POST "/api/v1/interlays/$INTERLAY/native-authority" \
  --body-file authority-action.json --content-type application/json --confirm

3. Verify the operation. Read the receipt through the same endpoint. Confirm serving_now and the full expected shard acknowledgment. Repeat the report’s benign and marked probes and check the backend observations.
4. Revoke or restore. Send revoke with the exact operation UUID. Mandatory protection can refuse traffic until a compatible operation is approved and activated. Verify the restored receipt and repeat the probes.

Vendor update. Use the advisory and its product-specific vendor references to select the fixed release for the exact installed product or package and release line. Follow its update instructions and confirm the version actually loaded by the service.

Measured comparison (live, 2026-11-11)

Performance trace (Eden telemetry, live 2026-11-11)

Measured with Eden's built-in request telemetry (gateway.request.baseline spans, read back through /api/v1/analytics/telemetry?signal=traces), not client wall-clock. Latency Eden introduces per remediation arm for this case:

Eden-added latency for the tier-2 remediation: benign requests complete in 315 µs mean (p50 283 µs, p95 578 µs) in-product, module evaluation included. Honest scope: lab fixtures on one host, fresh connection per measured request, warm requests only; module reactivated shards 2/2 with a fresh signed statement per measurement; spans carry the full authority lineage (module SHA-256, operation, publication). Not the EDEN-3640 performance qualification contract.

Tested against: eden-product-release:1.103.0-single (image sha256:809293e1f0b525ac…, build target eden_service_single, tooling revision 81a0724a…). Raw data: module2/telemetry-ab/signalk-telemetry.json and module2/tier1-ab/signalk-tier1.json.

Authority lifecycle and negatives

Driven through the full signed lifecycle (module2/evidence/signalk-module.json): enroll_key (Ed25519 public key), independent-host inventory, inspect, host approve, signed admit (prepared), activate — receipt serving_now: true, applied_shards == expected_shards (2/2). Negatives held: read-only inspect -> 403, tampered statement binding -> 400, flipped signature bit -> 403. revoke failed the interlay closed (503, nothing forwarded, zero backend effects); a fresh host approval plus a newly signed activation restored the module.

Honest scope

The fixture replicates the delivery shape with harmless marker effects; no real vendor component runs here. Bypass variants (encodings, alternate routes, other crafted members) are not bypass-tested and are out of scope; the rule is a lab-grade partial by construction. The vendor's fixed release remains the durable repair.

Cost record (per-CVE ledger)

$0.0000 USD (marginal session growth: 0 in + 0 out tokens, 0 turns; shared windows overlap).

Evidence appendix

• cve.now entry
• Raw evidence: gabriel-2026-11-11/module2/evidence/signalk-module.json
• Deployment: installed eden-product-release:1.103.0-single lab container (image sha256:809293e1f0b525ac04698d1fa8d7ffdc66cbee1ff690b082ba26b4d050f08416)
• Skill: eden-vulnerability-remediation

Decision flow

The diagram sketches the available source’s content decision after input metadata is available. Continue is a module decision; the host and backend still determine final forwarding and effects. This available source has a different hash from the source identity recorded for the tested binary.

Complete native module source

The complete available source for gabriel_signalk_v1 is reproduced below from the reviewed repository snapshot. The source SHA-256 is 5580eddb2860e56235896ea1414b737ad3a94522999de9f4a7c5d7e9bb70488c. Source identity mismatch: this case records db2ac5746c094214b31e9ba5ee94bb1ffd03c1062fad04b67f2352649f9c2ed2, which differs from the available listing. The listing cannot be identified as the exact source used to build the tested binary without further evidence. The case’s experiment status and limitations still apply, including any failed import, partial coverage, or withdrawn claim. Original source comments are preserved verbatim.

//! Gabriel module: refuse traversal in resources API queries (CVE-2026-123807 shape)
//!
//! CVE-2026-123807: Signal K v2 resources API path traversal reads
//! arbitrary JSON, including security settings with signing secrets.
//! This module refuses resources queries carrying traversal bytes
//! (plain and encoded); ordinary resource reads pass unchanged. no_std; no allocator, storage, background work or state.

#![no_std]

use core::mem::size_of;
use core::panic::PanicInfo;
use eden_gateway_remediation::message::{Availability, MessageInput};
use eden_gateway_remediation::module::{
    ApiHeader, CONTINUE, Decision, EDIT, EditSink, Edits, Failure, ModuleOutput, NEED_MORE, REFUSE, RemediationModule,
};
use eden_gateway_remediation::native_http_v3::{self as http, Api, Input, Request};

/// Route prefix in scope.
const ROUTE: &[u8] = b"/signalk/v1/resources";

/// The byte primitives this module refuses on that route.
static NEEDLES: [&[u8]; 4] = [b"../", b"..%2f", b"..%2F", b"..%5c"];


fn find_ignore_case_vol(haystack: &[u8], needle: &[u8]) -> Option<usize> {
    if haystack.len() < needle.len() || needle.is_empty() {
        return None;
    }
    let mut i = 0usize;
    while i + needle.len() <= haystack.len() {
        let mut j = 0usize;
        let mut same = true;
        while j < needle.len() {
            let h = unsafe { core::ptr::read_volatile(&haystack[i + j]) };
            let n = unsafe { core::ptr::read_volatile(&needle[j]) };
            if h.to_ascii_lowercase() != n.to_ascii_lowercase() {
                same = false;
                break;
            }
            j += 1;
        }
        if same {
            return Some(i);
        }
        i += 1;
    }
    None
}

fn find(haystack: &[u8], needle: &[u8]) -> Option<usize> {
    if haystack.len() < needle.len() || needle.is_empty() {
        return None;
    }
    let mut i = 0usize;
    while i + needle.len() <= haystack.len() {
        let mut j = 0usize;
        let mut same = true;
        while j < needle.len() {
            if haystack[i + j] != needle[j] {
                same = false;
                break;
            }
            j += 1;
        }
        if same {
            return Some(i);
        }
        i += 1;
    }
    None
}

fn find_ignore_case(haystack: &[u8], needle: &[u8]) -> Option<usize> {
    if haystack.len() < needle.len() || needle.is_empty() {
        return None;
    }
    let mut i = 0usize;
    while i + needle.len() <= haystack.len() {
        let mut j = 0usize;
        let mut same = true;
        while j < needle.len() {
            if haystack[i + j].to_ascii_lowercase() != needle[j].to_ascii_lowercase() {
                same = false;
                break;
            }
            j += 1;
        }
        if same {
            return Some(i);
        }
        i += 1;
    }
    None
}

struct gabriel_signalk_v1;

impl RemediationModule<Request<'_>> for gabriel_signalk_v1 {
    fn evaluate(&self, request: &Request<'_>, edits: &mut Edits<'_>) -> Result<Decision, Failure> {
        let _ = edits;
        let _ = match request.header_count() {
            Availability::Ready(count) => count,
            Availability::NeedMore => return Ok(Decision::NeedMore),
            Availability::Unavailable => return Err(Failure),
        };
        let message = request.message();
        let head = message.prefix();
        let line_end = head.iter().position(|&b| b == b'\r').unwrap_or(head.len());
        let request_line = &head[..line_end];
        let path_at = request_line.iter().position(|&b| b == b' ').unwrap_or(request_line.len());
        let target = &request_line[path_at + 1..];
        if !target.starts_with(ROUTE) {
            return Ok(Decision::Continue);
        }
        let q_at = target.iter().position(|&b| b == b'?');
        let query = match q_at {
            Some(at) => &target[at + 1..],
            None => return Ok(Decision::Continue),
        };
        if !message.is_complete() {
            return Ok(Decision::NeedMore);
        }
        if NEEDLES.iter().any(|n| find_ignore_case(query, n).is_some()) {
            return Ok(Decision::Refuse);
        }
        Ok(Decision::Continue)
    }
}

static API: Api = Api {
    header: ApiHeader { version: http::VERSION, table_size: size_of::<Api>() as u32 },
    input_size: size_of::<Input>() as u32,
    output_size: size_of::<ModuleOutput>() as u32,
    sink_size: size_of::<EditSink>() as u32,
    message_size: size_of::<MessageInput>() as u32,
    state_bytes: 0,
    capabilities: CONTINUE | REFUSE | NEED_MORE | EDIT,
    required_inputs: 0,
    evaluate: Some(evaluate),
};

unsafe extern "C" fn evaluate(input: *const Input, sink: *const EditSink, output: *mut ModuleOutput) -> i32 {
    unsafe { http::invoke(&gabriel_signalk_v1, input, sink, output) }
}

#[unsafe(no_mangle)]
pub extern "C" fn eden_http_remediation_v3() -> *const Api {
    &API
}

#[panic_handler]
fn panic(_information: &PanicInfo<'_>) -> ! {
    loop {
        core::hint::spin_loop();
    }
}