CVE-2026-55546

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 66% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

QWED-MCP is a deterministic verification gateway for MCP. Prior to 0.2.1, verify_math_expression() in src/qwed_mcp/engines/math_engine.py passes attacker-controlled expression and claimed_result strings directly to SymPy's parse_expr() after only normalizing caret syntax to Python exponent syntax, without restricting global_dict, removing Python built-ins, or validating the expression AST. Because parse_expr() calls Python's eval() with built-ins available, an attacker who can cause a downstream caller to pass untrusted input to this public library function can use Python import functionality to execute arbitrary operating-system commands as the qwed-mcp process user, read or modify accessible data, exfiltrate process secrets, or reach internal services. The default MCP tool registry does not expose verify_math_expression(), so exploitation requires a downstream integration that invokes the library API with attacker-controlled input. This issue is fixed in version 0.2.1.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

August 25, 2026

Last Modified

August 25, 2026

Advisory Details (4)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_pr, github_release.
github Patch Available🟡 PoC Available

Unsafe SymPy `parse_expr()` Remote Code Execution via Unsanitized Math Expression Input · Advisory · QWED-AI/qwed-mcp · GitHub

https://github.com/QWED-AI/qwed-mcp/security/advisories/GHSA-mw6r-2hvm-4rp2
github_release Patch Available

v0.2.1 - Critical Security Patch & PyJWT Update

Patch available: QWED-AI/qwed-mcp v0.2.1

https://github.com/QWED-AI/qwed-mcp/releases/tag/v0.2.1
github_pr Patch Available

chore(release): bump version to 0.2.1 for security patch release

Patch available: QWED-AI/qwed-mcp v0.2.1 (PR #22 merged 2026-06-13)

https://github.com/QWED-AI/qwed-mcp/pull/22
github_commit Patch Available

commit 362e61892052 (QWED-AI/qwed-mcp)

Patch available: QWED-AI/qwed-mcp v0.2.1 (contains commit 362e61892052)

https://github.com/QWED-AI/qwed-mcp/commit/362e61892052e250c56cb1ee852024d6f98c467b

Vendor Advisories for CVE-2026-55546(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
qwed-mcp0.1.00.2.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 13× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 02:32 UTCEG score recompute
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-29 00:16 UTCEG score recompute
  4. 2026-08-28 21:41 UTCEPSS rescore
  5. 2026-08-27 15:40 UTCEG score recompute
  6. 2026-08-27 14:25 UTCEPSS rescore
  7. 2026-08-26 17:46 UTCEG score recompute
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 19:22 UTCEG score recompute
  10. 2026-08-25 18:31 UTCEG score recompute
  11. 2026-08-25 16:24 UTCEG score recompute
  12. 2026-08-25 15:30 UTCEG score recompute
  13. 2026-08-25 15:29 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55546?
CVE-2026-55546 is a critical vulnerability published on August 25, 2026. QWED-MCP is a deterministic verification gateway for MCP. Prior to 0.2.1, verifymathexpression() in src/qwedmcp/engines/mathengine.py passes attacker-controlled expression and claimedresult strings directly to SymPy's parseexpr() after only normalizing caret syntax to Python exponent syntax,…
When was CVE-2026-55546 disclosed?
CVE-2026-55546 was first published in the National Vulnerability Database on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55546 actively exploited?
CVE-2026-55546 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.0% of all scored CVEs.
What is the CVSS score of CVE-2026-55546?
CVE-2026-55546 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-55546?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55546, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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