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🐍 PyPI
Not in CISA KEV
LOW severity

CVE-2026-44219 — ciguard

LOW

CVE-2026-44219 is a low-severity (CVSS 3.7) CWE-770 vulnerability in ciguard. A fix is available for ciguard — see the affected versions and patch details below.

ciguard: SCA HTTP client reads response body without size cap

Also known asGHSA-xw8c-rrvx-f7xqPYSEC-2026-2410
Published
May 12, 2026
Updated
Aug 12, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

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.

How urgent is this, really

CVE-2026-44219 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐍ciguard

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Both SCA HTTP clients (src/ciguard/analyzer/sca/osv.py and src/ciguard/analyzer/sca/endoflife.py) call payload = json.loads(resp.read().decode('utf-8')) without a maximum-bytes cap. A hostile or compromised endoflife.date / OSV.dev (or a successful TLS MITM) could return a multi-GB response, exhausting the ciguard process's memory.

Threat scenario

ciguard process memory exhaustion → OOM kill or system swap thrash. Realistic when ciguard runs in CI with a limited memory budget (typical: 4-8 GB). No data integrity or confidentiality impact.

Realism caveat: both URLs are hardcoded HTTPS, so this is a low-realism threat (HTTPS prevents MITM unless the attacker controls a trusted CA or hijacks DNS in a way that doesn't trigger cert validation). The unbounded read is structural defence-in-depth, not a directly exploitable bug today.

Patch

  • New MAX_RESPONSE_BYTES = 5 * 1024 * 1024 (5 MB) constant in both modules.
  • body = resp.read(MAX_RESPONSE_BYTES + 1) with overflow check returns None (caller falls back to stale cache).
  • 3 regression tests in tests/test_sca_rules.py::TestSCAResponseSizeCap.

Discovery

Found during ciguard's first self-conducted pentest cycle, 2026-04-26.

CVSS Scoring

  • CVSS v3.1: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L — 3.7 (Low)
  • CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N — first.org calc 3.1 (Low); GitHub's calc 6.3 (Medium). Vector is correct — choosing v3.1 as the structured score keeps the consistent Low rating across consumers.

Reproduction

Monkey-patch urllib.request.urlopen to return a fake 50 MB response; observe memory growth before/after the call. Pre-fix: process memory grows by ~50 MB. Post-fix: _fetch returns None, memory growth bounded to MAX_RESPONSE_BYTES.

References

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIciguard≥ 0.6.0&&< 0.8.20.8.2pip install --upgrade 'ciguard==0.8.2'

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ciguard, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update ciguard to 0.8.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44219 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-44219 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-44219. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary Both SCA HTTP clients (`src/ciguard/analyzer/sca/osv.py` and `src/ciguard/analyzer/sca/endoflife.py`) call `payload = json.loads(resp.read().decode('utf-8'))` without a maximum-bytes cap. A hostile or compromised endoflife.date / OSV.dev (or a successful TLS MITM) could return a multi-GB response, exhausting the ciguard process's memory. ## Threat scenario ciguard process memory exhaustion → OOM kill or system swap thrash. Realistic when ciguard runs in CI with a limited memory budget (typical: 4-8 GB). No data integrity or confidentiality impact. **Realism caveat:** both URLs a
O3 Security · Impact-Aware SCA

Is CVE-2026-44219 in your dependencies?

O3 Security finds CVE-2026-44219 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works
CVE-2026-44219: ciguard (Low 3.7) | O3 Security