CVE-2026-46689 — scim_proto
CVE-2026-46689 is a CWE-248 vulnerability in scim_proto. A fix is available for scim_proto — see the affected versions and patch details below.
Kanidm: Unauthenticated process abort via SCIM filter stack exhaustion
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-46689.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
scim_proto🦀kanidm_protoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Kanidm is an identity management platform. Prior to version 1.9.3, a single unauthenticated GET to any /scim/v1/... endpoint with a ?filter= query string of a few thousand nested parentheses (≈ 4–12 KB) drives the recursive-descent PEG parser past the worker thread's stack guard page. Rust responds to stack overflow with std::process::abort() — the entire kanidmd process exits. The parse runs inside axum's Query<ScimEntryGetQuery> extractor, before any handler body and therefore before any ACL check. This issue has been patched in version 1.9.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | scim_proto | all versions | 1.9.3cargo update -p scim_proto --precise 1.9.3 |
| 🦀crates.io | kanidm_proto | all versions | 1.9.3cargo update -p kanidm_proto --precise 1.9.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for scim_proto, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update scim_proto to 1.9.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-46689 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-46689 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-46689. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-46689 in your dependencies?
O3 Security finds CVE-2026-46689 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.