CVE-2026-73248

HIGHPre-NVD 8.58.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 96% 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
8.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.5Exploit: Elevated riskExposed: 0

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

calibre is an e-book manager. Prior to 9.12.0, calibre processes attacker-controlled composite_template metadata from a malicious EPUB, OPF, PDF, or similar file through program: and a nested template() call whose formatter does not inherit allow_python_templates=False, allowing a nested python: template to reach compile_python_template and execute arbitrary Python code when the file is opened or imported. This issue is fixed in version 9.12.0.

CVSS v3
8.5
EG Score
8.5(medium)
EG Risk
54(Track*)
EG Risk 54/100SSVC: 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
Severity85% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

August 11, 2026

Last Modified

August 12, 2026

Advisory Details (3)

Auto-updated Aug 11, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

version 9.12.0

Patch available: kovidgoyal/calibre v9.12.0

https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0
github_commit Patch Available

commit dac999045837 (kovidgoyal/calibre)

Patch available: kovidgoyal/calibre v9.12.0 (contains commit dac999045837)

https://github.com/kovidgoyal/calibre/commit/dac9990458374a81a5372a768bba6527d965aac8
github Patch Available🟡 PoC Available

Arbitrary code execution via nested `template()` that bypasses Python template restrictions · Advisory · kovidgoyal/calibre · GitHub

https://github.com/kovidgoyal/calibre/security/advisories/GHSA-4f7g-rjfp-hmvx

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 32× 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. 2026-08-25 18:10 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 19:43 UTCEG score recompute
  4. 2026-08-23 09:53 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-22 00:18 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 01:55 UTCEG score recompute
  9. 2026-08-20 22:56 UTCEPSS rescore
  10. 2026-08-20 03:31 UTCEG score recompute
  11. 2026-08-19 17:04 UTCEPSS rescore
  12. 2026-08-18 17:50 UTCEG score recompute
  13. 2026-08-18 13:49 UTCEPSS rescore
  14. 2026-08-18 13:49 UTCEPSS rescore
  15. 2026-08-17 19:15 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 19:08 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 07:56 UTCEG score recompute
  21. 2026-08-16 02:15 UTCEPSS rescore
  22. 2026-08-15 09:33 UTCEG score recompute
  23. 2026-08-15 01:31 UTCEPSS rescore
  24. 2026-08-13 23:58 UTCEG score recompute
  25. 2026-08-13 22:00 UTCEPSS rescore
Show 7 more
  1. 2026-08-13 01:35 UTCEG score recompute
  2. 2026-08-12 14:23 UTCEG score recompute
  3. 2026-08-12 13:59 UTCEG score recompute
  4. 2026-08-12 13:51 UTCEPSS rescore
  5. 2026-08-11 22:20 UTCEG score recompute
  6. 2026-08-11 22:06 UTCEG score recompute
  7. 2026-08-11 22:05 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-73248?
CVE-2026-73248 is a high vulnerability published on August 11, 2026. calibre is an e-book manager. Prior to 9.12.0, calibre processes attacker-controlled compositetemplate metadata from a malicious EPUB, OPF, PDF, or similar file through program: and a nested template() call whose formatter does not inherit allowpythontemplates=False, allowing a nested python:…
When was CVE-2026-73248 disclosed?
CVE-2026-73248 was first published in the National Vulnerability Database on August 11, 2026, with the most recent update on August 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73248 actively exploited?
CVE-2026-73248 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 95.8% of all scored CVEs.
What is the CVSS score of CVE-2026-73248?
CVE-2026-73248 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2026-73248?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73248, 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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