CVE-2026-53951

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 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
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

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

Copier is a library and CLI app for rendering project templates. In versions 9.5.0 through 9.15.1, the trust setting's prefix match (copier/_settings.py) compares the template URL against a trusted prefix with a raw str.startswith and no path normalization, while the URL is normalized when the template is actually fetched (Path.resolve() for local paths; libcurl dot-segment removal for https). A template reference that textually starts with a trusted prefix but contains .. is therefore granted trust yet resolves to a different, attacker-controlled template, whose tasks / migrations / jinja_extensions then run without the --trust prompt — arbitrary command execution. Version 9.15.2 patches the issue.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
8.7%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 10, 2026

Advisory Details (2)

Auto-updated Jul 8, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github.
github Patch Available🟡 PoC Available

Copier: trust-prefix bypass via path traversal runs tasks unprompted · Advisory · copier-org/copier · GitHub

https://github.com/copier-org/copier/security/advisories/GHSA-9gmc-jqmh-3rvm
github_release Patch Available

v9.15.2 (2026-06-12)

Patch available: copier-org/copier v9.15.2

https://github.com/copier-org/copier/releases/tag/v9.15.2

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 27× in last 7d / 29× 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. 2026-07-15 21:50 UTCEG score recompute
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 16:57 UTCEPSS rescore
  4. 2026-07-15 10:15 UTCEG score recompute
  5. 2026-07-15 02:00 UTCEPSS rescore
  6. 2026-07-15 02:00 UTCEPSS rescore
  7. 2026-07-14 22:38 UTCEG score recompute
  8. 2026-07-14 11:03 UTCEG score recompute
  9. 2026-07-13 23:21 UTCEG score recompute
  10. 2026-07-13 22:31 UTCEPSS rescore
  11. 2026-07-13 11:46 UTCEG score recompute
  12. 2026-07-13 06:13 UTCEPSS rescore
  13. 2026-07-13 06:13 UTCEPSS rescore
  14. 2026-07-13 00:09 UTCEG score recompute
  15. 2026-07-12 12:35 UTCEG score recompute
  16. 2026-07-12 05:46 UTCEPSS rescore
  17. 2026-07-12 01:00 UTCEG score recompute
  18. 2026-07-11 13:25 UTCEG score recompute
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-11 01:50 UTCEG score recompute
  22. 2026-07-10 14:14 UTCEG score recompute
  23. 2026-07-10 02:37 UTCEG score recompute
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-09 19:10 UTCEPSS rescore
Show 4 more
  1. 2026-07-09 14:58 UTCEG score recompute
  2. 2026-07-09 03:23 UTCEG score recompute
  3. 2026-07-08 15:46 UTCEG score recompute
  4. 2026-07-08 15:45 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-53951?
CVE-2026-53951 is a high vulnerability published on July 8, 2026. Copier is a library and CLI app for rendering project templates. In versions 9.5.0 through 9.15.1, the trust setting's prefix match (copier/settings.py) compares the template URL against a trusted prefix with a raw str.startswith and no path normalization, while the URL is normalized when the…
When was CVE-2026-53951 disclosed?
CVE-2026-53951 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53951 actively exploited?
CVE-2026-53951 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 8.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53951?
CVE-2026-53951 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-53951?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53951, 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.

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