CVE-2026-19591

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-01. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: None knownExposed: 0

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

OpenAI Codex CLI for Windows, macOS, and Linux and Codex Desktop for Windows and macOS misclassified certain PowerShell commands as safe because their command-safety parser interpreted PowerShell's stop-parsing token (--%) differently than PowerShell itself. If a user opens an attacker-prepared repository and Codex follows its instructions, Codex can run a file-writing Git command without requesting user approval. On macOS and Linux, exploitation additionally requires separately installed PowerShell Core (pwsh) to be invoked. If filesystem protections permit the write, the command can modify Codex's configuration. If Codex later loads the modified configuration, it can launch an attacker-controlled MCP server and execute code with the user's privileges, allowing it to read, change, or delete files accessible to that account. The approval bypass does not disable filesystem sandboxing; the default filesystem sandbox on macOS and Linux can prevent writes outside permitted locations.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity88% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

September 1, 2026

Last Modified

September 2, 2026

Advisory Details (1)

Auto-updated Sep 2, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

[codex] treat PowerShell stop-parsing forms as unsupported

Fix merged in openai/codex PR #22643 on 2026-05-14 — awaiting tagged release

https://github.com/openai/codex/pull/22643

Vendor Advisories for CVE-2026-19591(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 28× in last 7d / 72× 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. 2026-09-19 06:15 UTCEG score recompute
  2. 2026-09-19 06:14 UTCGHSA enrichment
  3. 2026-09-18 19:27 UTCEPSS rescore
  4. 2026-09-18 19:11 UTCGHSA enrichment
  5. 2026-09-18 08:03 UTCGHSA enrichment
  6. 2026-09-17 20:59 UTCEG score recompute
  7. 2026-09-17 20:59 UTCGHSA enrichment
  8. 2026-09-17 09:55 UTCGHSA enrichment
  9. 2026-09-16 22:51 UTCEG score recompute
  10. 2026-09-16 22:50 UTCGHSA enrichment
  11. 2026-09-16 14:07 UTCEPSS rescore
  12. 2026-09-16 11:46 UTCEG score recompute
  13. 2026-09-16 11:46 UTCGHSA enrichment
  14. 2026-09-16 05:14 UTCEPSS rescore
  15. 2026-09-16 00:43 UTCGHSA enrichment
  16. 2026-09-15 13:24 UTCEG score recompute
  17. 2026-09-15 13:24 UTCGHSA enrichment
  18. 2026-09-15 02:20 UTCGHSA enrichment
  19. 2026-09-14 15:10 UTCGHSA enrichment
  20. 2026-09-14 04:06 UTCGHSA enrichment
  21. 2026-09-13 17:03 UTCEG score recompute
  22. 2026-09-13 17:03 UTCGHSA enrichment
  23. 2026-09-13 16:46 UTCEPSS rescore
  24. 2026-09-13 05:59 UTCGHSA enrichment
  25. 2026-09-12 18:55 UTCEG score recompute
Show 47 more
  1. 2026-09-12 18:55 UTCGHSA enrichment
  2. 2026-09-12 15:00 UTCEPSS rescore
  3. 2026-09-12 07:51 UTCGHSA enrichment
  4. 2026-09-11 20:48 UTCEG score recompute
  5. 2026-09-11 20:48 UTCGHSA enrichment
  6. 2026-09-11 14:52 UTCEPSS rescore
  7. 2026-09-11 09:43 UTCEG score recompute
  8. 2026-09-11 09:43 UTCGHSA enrichment
  9. 2026-09-11 09:36 UTCEPSS rescore
  10. 2026-09-10 22:39 UTCGHSA enrichment
  11. 2026-09-10 11:35 UTCEG score recompute
  12. 2026-09-10 11:35 UTCGHSA enrichment
  13. 2026-09-10 09:34 UTCEPSS rescore
  14. 2026-09-09 23:36 UTCGHSA enrichment
  15. 2026-09-09 10:32 UTCGHSA enrichment
  16. 2026-09-08 23:22 UTCEG score recompute
  17. 2026-09-08 23:22 UTCGHSA enrichment
  18. 2026-09-08 22:00 UTCEPSS rescore
  19. 2026-09-08 08:30 UTCGHSA enrichment
  20. 2026-09-07 21:26 UTCEG score recompute
  21. 2026-09-07 21:26 UTCGHSA enrichment
  22. 2026-09-07 16:01 UTCEPSS rescore
  23. 2026-09-07 10:23 UTCGHSA enrichment
  24. 2026-09-06 23:19 UTCEG score recompute
  25. 2026-09-06 23:19 UTCGHSA enrichment
  26. 2026-09-06 13:47 UTCEPSS rescore
  27. 2026-09-06 12:15 UTCGHSA enrichment
  28. 2026-09-06 01:09 UTCEG score recompute
  29. 2026-09-06 01:08 UTCGHSA enrichment
  30. 2026-09-05 14:03 UTCGHSA enrichment
  31. 2026-09-05 02:59 UTCGHSA enrichment
  32. 2026-09-04 15:54 UTCEG score recompute
  33. 2026-09-04 15:54 UTCGHSA enrichment
  34. 2026-09-04 05:06 UTCEPSS rescore
  35. 2026-09-04 04:49 UTCGHSA enrichment
  36. 2026-09-03 17:41 UTCGHSA enrichment
  37. 2026-09-03 06:37 UTCEG score recompute
  38. 2026-09-03 06:36 UTCGHSA enrichment
  39. 2026-09-02 19:33 UTCGHSA enrichment
  40. 2026-09-02 18:43 UTCEG score recompute▲ 8.80
  41. 2026-09-02 18:43 UTCGHSA enrichment
  42. 2026-09-02 18:41 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  43. 2026-09-02 14:11 UTCEPSS rescore
  44. 2026-09-01 21:07 UTCGHSA enrichment
  45. 2026-09-01 18:22 UTCNVD update
  46. 2026-09-01 17:22 UTCEG score recompute
  47. 2026-09-01 17:22 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-19591?
CVE-2026-19591 is a high vulnerability published on September 1, 2026. OpenAI Codex CLI for Windows, macOS, and Linux and Codex Desktop for Windows and macOS misclassified certain PowerShell commands as safe because their command-safety parser interpreted PowerShell's stop-parsing token (--%) differently than PowerShell itself. If a user opens an attacker-prepared…
When was CVE-2026-19591 disclosed?
CVE-2026-19591 was first published in the National Vulnerability Database on September 1, 2026, with the most recent update on September 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-19591 actively exploited?
CVE-2026-19591 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 76.5% of all scored CVEs.
What is the CVSS score of CVE-2026-19591?
CVE-2026-19591 has a CVSS v3.1 base score of 8.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-19591?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-19591, 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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