CVE-2026-55244

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% 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
Elevated
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.0Exploit: Elevated riskExposed: 0

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

ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter's safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9.

CVSS v3
5.0
EG Score
5.0(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

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
Severity50% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 16, 2026

Advisory Details (5)

Auto-updated Sep 14, 2026
🔬 Proof of concept available. Patch available. Sources: github_pr, github_release, github, github_commit.
github Patch Available🟡 PoC Available

Sandbox Escape via BaseException Subclasses in asteval 1.0.8 · Advisory · lmfit/asteval · GitHub

Affected: 1.0.6. This vector is present in

https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77
github_release Patch Available

1.0.9

Patch available: lmfit/asteval 1.0.9

https://github.com/lmfit/asteval/releases/tag/1.0.9
github_pr Patch Available

Fix exiting exceptions

Patch available: lmfit/asteval 1.0.9 (PR #153 merged 2026-06-11)

https://github.com/lmfit/asteval/pull/153
github_commit Patch Available

commit c49c99a67acb (lmfit/asteval)

Patch available: lmfit/asteval 1.0.9 (contains commit c49c99a67acb)

https://github.com/lmfit/asteval/commit/c49c99a67acb63eb7410231932250bd820380e45
github_commit Patch Available

commit 9c625b3674f8 (lmfit/asteval)

Patch available: lmfit/asteval 1.0.9 (contains commit 9c625b3674f8)

https://github.com/lmfit/asteval/commit/9c625b3674f8d05f206708bb85afca17a87694a4

Vendor Advisories for CVE-2026-55244(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
asteval0.9 ... 1.0.8 (43 versions)1.0.9—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 10× 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. 2026-09-18 23:20 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 21:19 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-16 17:52 UTCEG score recompute
  6. 2026-09-16 16:58 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescore
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-14 20:27 UTCEG score recompute
  10. 2026-08-20 17:42 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-55244?
CVE-2026-55244 is a medium vulnerability published on August 20, 2026. ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROMPY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception…
When was CVE-2026-55244 disclosed?
CVE-2026-55244 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55244 actively exploited?
CVE-2026-55244 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 91.0% of all scored CVEs.
What is the CVSS score of CVE-2026-55244?
CVE-2026-55244 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2026-55244?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55244, 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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